I have followed below instrustions 

• Remove unused plugins from your installation
• Remove deprecated plugins from your installation
• Remove plugins with security issues from your installation

Here are details from the script
Jenkins: 2.277.3
OS: Windows Server 2012 - 6.2
—
ace-editor:1.1
ant:1.11
antisamy-markup-formatter:1.6
apache-httpcomponents-client-4-api:4.5.13-1.0
applitools-eyes:1.13
authentication-tokens:1.4
backup:1.6.1
bitbucket-oauth:0.10
bitbucket:1.1.27
block-build-final-project:1.0
blueocean-autofavorite:1.2.4
blueocean-bitbucket-pipeline:1.24.6
blueocean-commons:1.24.6
blueocean-config:1.24.6
blueocean-core-js:1.24.6
blueocean-dashboard:1.24.6
blueocean-display-url:2.4.1
blueocean-events:1.24.6
blueocean-git-pipeline:1.24.6
blueocean-github-pipeline:1.24.6
blueocean-i18n:1.24.6
blueocean-jira:1.24.6
blueocean-jwt:1.24.6
blueocean-personalization:1.24.6
blueocean-pipeline-api-impl:1.24.6
blueocean-pipeline-editor:1.24.6
blueocean-pipeline-scm-api:1.24.6
blueocean-rest-impl:1.24.6
blueocean-rest:1.24.6
blueocean-web:1.24.6
blueocean:1.24.6
bootstrap4-api:4.6.0-3
bouncycastle-api:2.20
branch-api:2.6.3
build-blocker-plugin:1.7.7
build-timeout:1.20
categorized-view:1.10
checks-api:1.7.0
cloudbees-bitbucket-branch-source:2.9.8
cloudbees-folder:6.15
command-launcher:1.5
conditional-buildstep:1.4.1
copyartifact:1.46
credentials-binding:1.24
credentials:2.3.18
cucumber-reports:5.5.0
cucumber-testresult-plugin:0.10.1
cucumber-trends-report:1.3
CucumberReportMailer:1.0-SNAPSHOT (private-03/03/2020 20:04-lagisesu)
discard-old-build:1.05
display-url-api:2.3.4
docker-commons:1.17
docker-workflow:1.26
durable-task:1.35
echarts-api:5.1.0-2
email-ext:2.82
external-monitor-job:1.7
favorite:2.3.3
font-awesome-api:5.15.2-2
git-client:3.7.1
git-server:1.9
git:4.7.1
gitbucket:0.8
github-api:1.123
github-branch-source:2.10.2
github-oauth:0.33
github:1.33.1
global-build-stats:1.5
gradle:1.36
groovy:2.3
handlebars:3.0.8
handy-uri-templates-2-api:2.1.8-1.0
hp-application-automation-tools-plugin:6.8
htmlpublisher:1.25
jackson2-api:2.12.3
javadoc:1.6
jdk-tool:1.5
jenkins-design-language:1.24.6
jira:3.2.1
jjwt-api:0.11.2-9.c8b45b8bb173
job-import-plugin:3.4
jobConfigHistory:2.27
join:1.21
jquery-detached:1.2.1
jquery-ui:1.0.2
jquery:1.12.4-1
jquery3-api:3.6.0-1
jsch:0.1.55.2
junit:1.49
ldap:2.6
lockable-resources:2.10
mail-watcher-plugin:1.16
mailer:1.34
mapdb-api:1.0.9.0
matrix-auth:2.6.6
matrix-project:1.18
maven-plugin:3.10
mercurial:2.14
metrics:4.0.2.7
mock-security-realm:1.5
momentjs:1.1.1
monitoring:1.87.0
naginator:1.18.1
notification:1.14
oic-auth:1.8
okhttp-api:3.14.9
ownership:0.13.0
pam-auth:1.6
parameterized-trigger:2.40
pipeline-build-step:2.13
pipeline-github-lib:1.0
pipeline-graph-analysis:1.10
pipeline-input-step:2.12
pipeline-milestone-step:1.3.2
pipeline-model-api:1.8.4
pipeline-model-declarative-agent:1.1.1
pipeline-model-definition:1.8.4
pipeline-model-extensions:1.8.4
pipeline-rest-api:2.19
pipeline-stage-step:2.5
pipeline-stage-tags-metadata:1.8.4
pipeline-stage-view:2.19
plain-credentials:1.7
plugin-util-api:2.1.0
poll-mailbox-trigger-plugin:1.026
popper-api:1.16.1-2
postbuild-task:1.9
pubsub-light:1.13
purge-job-history:1.6
queue-cleanup:1.4
repository:1.3
resource-disposer:0.15
role-strategy:3.1.1
run-condition:1.5
scm-api:2.6.4
script-security:1.76
snakeyaml-api:1.27.0
sse-gateway:1.24
ssh-credentials:1.18.1
ssh-slaves:1.30.2
structs:1.22
subversion:2.14.0
support-core:2.73
testng-plugin:1.15
thinBackup:1.10
timestamper:1.12
token-macro:2.15
trilead-api:1.0.13
variant:1.4
view-job-filters:2.3
windows-slaves:1.7
workflow-aggregator:2.6
workflow-api:2.42
workflow-basic-steps:2.23
workflow-cps-global-lib:2.18
workflow-cps:2.90
workflow-durable-task-step:2.38
workflow-job:2.40
workflow-multibranch:2.23
workflow-scm-step:2.12
workflow-step-api:2.23
workflow-support:3.8
ws-cleanup:0.39
cucumber-perf:2.0.9
cucumber-living-documentation:3.2

Also seeing this errors in the console log

See my description in https://issues.jenkins.io/browse/JENKINS-65304?focusedCommentId=408437&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-408437 . I'm unable to duplicate the problem you're describing.

More details will be needed, like the details of the specific job that won't save or if all defined jobs won't save or only one or if the problem persists when you remove the CucumberReportMailer:1.0-SNAPSHOT plugin

Hello markewaite, thank you for the analysis. 

please find the updated information, I've also uninstalled the custom plugin.
Jenkins: 2.277.3
OS: Windows 10 - 10.0
—
ace-editor:1.1
ant:1.11
antisamy-markup-formatter:2.1
apache-httpcomponents-client-4-api:4.5.13-1.0
applitools-eyes:1.13
authentication-tokens:1.4
backup:1.6.1
bitbucket-oauth:0.10
bitbucket:1.1.27
block-build-final-project:1.0
blueocean-autofavorite:1.2.4
blueocean-bitbucket-pipeline:1.24.6
blueocean-commons:1.24.6
blueocean-config:1.24.6
blueocean-core-js:1.24.6
blueocean-dashboard:1.24.6
blueocean-display-url:2.4.1
blueocean-events:1.24.6
blueocean-git-pipeline:1.24.6
blueocean-github-pipeline:1.24.6
blueocean-i18n:1.24.6
blueocean-jira:1.24.6
blueocean-jwt:1.24.6
blueocean-personalization:1.24.6
blueocean-pipeline-api-impl:1.24.6
blueocean-pipeline-editor:1.24.6
blueocean-pipeline-scm-api:1.24.6
blueocean-rest-impl:1.24.6
blueocean-rest:1.24.6
blueocean-web:1.24.6
blueocean:1.24.6
bootstrap4-api:4.6.0-3
bouncycastle-api:2.20
branch-api:2.6.3
build-blocker-plugin:1.7.7
build-timeout:1.20
categorized-view:1.10
checks-api:1.7.0
cloudbees-bitbucket-branch-source:2.9.8
cloudbees-folder:6.15
command-launcher:1.5
conditional-buildstep:1.4.1
copyartifact:1.46
credentials-binding:1.24
credentials:2.3.18
cucumber-reports:5.5.0
cucumber-testresult-plugin:0.10.1
cucumber-trends-report:1.3
discard-old-build:1.05
display-url-api:2.3.4
docker-commons:1.17
docker-workflow:1.26
durable-task:1.35
echarts-api:5.1.0-2
email-ext:2.82
external-monitor-job:1.7
favorite:2.3.3
font-awesome-api:5.15.2-2
git-client:3.7.1
git-server:1.9
git:4.7.1
gitbucket:0.8
github-api:1.123
github-branch-source:2.10.2
github-oauth:0.33
github:1.33.1
global-build-stats:1.5
gradle:1.36
groovy:2.3
handlebars:3.0.8
handy-uri-templates-2-api:2.1.8-1.0
hp-application-automation-tools-plugin:6.8
htmlpublisher:1.25
jackson2-api:2.12.3
javadoc:1.6
jdk-tool:1.5
jenkins-design-language:1.24.6
jira:3.2.1
jjwt-api:0.11.2-9.c8b45b8bb173
job-import-plugin:3.4
jobConfigHistory:2.27
join:1.21
jquery-detached:1.2.1
jquery:1.12.4-1
jquery3-api:3.6.0-1
jsch:0.1.55.2
junit:1.49
ldap:2.6
lockable-resources:2.10
mail-watcher-plugin:1.16
mailer:1.34
mapdb-api:1.0.9.0
matrix-auth:2.6.6
matrix-project:1.18
maven-plugin:3.10
mercurial:2.14
metrics:4.0.2.7
mock-security-realm:1.5
momentjs:1.1.1
monitoring:1.87.0
naginator:1.18.1
notification:1.14
oic-auth:1.8
okhttp-api:3.14.9
ownership:0.13.0
pam-auth:1.6
parameterized-trigger:2.40
pipeline-build-step:2.13
pipeline-github-lib:1.0
pipeline-graph-analysis:1.10
pipeline-input-step:2.12
pipeline-milestone-step:1.3.2
pipeline-model-api:1.8.4
pipeline-model-definition:1.8.4
pipeline-model-extensions:1.8.4
pipeline-rest-api:2.19
pipeline-stage-step:2.5
pipeline-stage-tags-metadata:1.8.4
pipeline-stage-view:2.19
plain-credentials:1.7
plugin-util-api:2.1.0
poll-mailbox-trigger-plugin:1.026
popper-api:1.16.1-2
postbuild-task:1.9
pubsub-light:1.13
purge-job-history:1.6
queue-cleanup:1.4
repository:1.3
resource-disposer:0.15
role-strategy:3.1.1
run-condition:1.5
scm-api:2.6.4
script-security:1.76
snakeyaml-api:1.27.0
sse-gateway:1.24
ssh-credentials:1.18.1
ssh-slaves:1.30.2
structs:1.22
subversion:2.14.0
support-core:2.73
testng-plugin:1.15
thinBackup:1.10
timestamper:1.12
token-macro:2.15
trilead-api:1.0.13
variant:1.4
view-job-filters:2.3
windows-slaves:1.7
workflow-aggregator:2.6
workflow-api:2.42
workflow-basic-steps:2.23
workflow-cps-global-lib:2.18
workflow-cps:2.90
workflow-durable-task-step:2.38
workflow-job:2.40
workflow-multibranch:2.23
workflow-scm-step:2.12
workflow-step-api:2.23
workflow-support:3.8
ws-cleanup:0.39
Result: [Plugin:ace-editor, Plugin:ant, Plugin:antisamy-markup-formatter, Plugin:apache-httpcomponents-client-4-api, Plugin:applitools-eyes, Plugin:authentication-tokens, Plugin:backup, Plugin:bitbucket-oauth, Plugin:bitbucket, Plugin:block-build-final-project, Plugin:blueocean-autofavorite, Plugin:blueocean-bitbucket-pipeline, Plugin:blueocean-commons, Plugin:blueocean-config, Plugin:blueocean-core-js, Plugin:blueocean-dashboard, Plugin:blueocean-display-url, Plugin:blueocean-events, Plugin:blueocean-git-pipeline, Plugin:blueocean-github-pipeline, Plugin:blueocean-i18n, Plugin:blueocean-jira, Plugin:blueocean-jwt, Plugin:blueocean-personalization, Plugin:blueocean-pipeline-api-impl, Plugin:blueocean-pipeline-editor, Plugin:blueocean-pipeline-scm-api, Plugin:blueocean-rest-impl, Plugin:blueocean-rest, Plugin:blueocean-web, Plugin:blueocean, Plugin:bootstrap4-api, Plugin:bouncycastle-api, Plugin:branch-api, Plugin:build-blocker-plugin, Plugin:build-timeout, Plugin:categorized-view, Plugin:checks-api, Plugin:cloudbees-bitbucket-branch-source, Plugin:cloudbees-folder, Plugin:command-launcher, Plugin:conditional-buildstep, Plugin:copyartifact, Plugin:credentials-binding, Plugin:credentials, Plugin:cucumber-reports, Plugin:cucumber-testresult-plugin, Plugin:cucumber-trends-report, Plugin:discard-old-build, Plugin:display-url-api, Plugin:docker-commons, Plugin:docker-workflow, Plugin:durable-task, Plugin:echarts-api, Plugin:email-ext, Plugin:external-monitor-job, Plugin:favorite, Plugin:font-awesome-api, Plugin:git-client, Plugin:git-server, Plugin:git, Plugin:gitbucket, Plugin:github-api, Plugin:github-branch-source, Plugin:github-oauth, Plugin:github, Plugin:global-build-stats, Plugin:gradle, Plugin:groovy, Plugin:handlebars, Plugin:handy-uri-templates-2-api, Plugin:hp-application-automation-tools-plugin, Plugin:htmlpublisher, Plugin:jackson2-api, Plugin:javadoc, Plugin:jdk-tool, Plugin:jenkins-design-language, Plugin:jira, Plugin:jjwt-api, Plugin:job-import-plugin, Plugin:jobConfigHistory, Plugin:join, Plugin:jquery-detached, Plugin:jquery, Plugin:jquery3-api, Plugin:jsch, Plugin:junit, Plugin:ldap, Plugin:lockable-resources, Plugin:mail-watcher-plugin, Plugin:mailer, Plugin:mapdb-api, Plugin:matrix-auth, Plugin:matrix-project, Plugin:maven-plugin, Plugin:mercurial, Plugin:metrics, Plugin:mock-security-realm, Plugin:momentjs, Plugin:monitoring, Plugin:naginator, Plugin:notification, Plugin:oic-auth, Plugin:okhttp-api, Plugin:ownership, Plugin:pam-auth, Plugin:parameterized-trigger, Plugin:pipeline-build-step, Plugin:pipeline-github-lib, Plugin:pipeline-graph-analysis, Plugin:pipeline-input-step, Plugin:pipeline-milestone-step, Plugin:pipeline-model-api, Plugin:pipeline-model-definition, Plugin:pipeline-model-extensions, Plugin:pipeline-rest-api, Plugin:pipeline-stage-step, Plugin:pipeline-stage-tags-metadata, Plugin:pipeline-stage-view, Plugin:plain-credentials, Plugin:plugin-util-api, Plugin:poll-mailbox-trigger-plugin, Plugin:popper-api, Plugin:postbuild-task, Plugin:pubsub-light, Plugin:purge-job-history, Plugin:queue-cleanup, Plugin:repository, Plugin:resource-disposer, Plugin:role-strategy, Plugin:run-condition, Plugin:scm-api, Plugin:script-security, Plugin:snakeyaml-api, Plugin:sse-gateway, Plugin:ssh-credentials, Plugin:ssh-slaves, Plugin:structs, Plugin:subversion, Plugin:support-core, Plugin:testng-plugin, Plugin:thinBackup, Plugin:timestamper, Plugin:token-macro, Plugin:trilead-api, Plugin:variant, Plugin:view-job-filters, Plugin:windows-slaves, Plugin:workflow-aggregator, Plugin:workflow-api, Plugin:workflow-basic-steps, Plugin:workflow-cps-global-lib, Plugin:workflow-cps, Plugin:workflow-durable-task-step, Plugin:workflow-job, Plugin:workflow-multibranch, Plugin:workflow-scm-step, Plugin:workflow-step-api, Plugin:workflow-support, Plugin:ws-cleanup]

markewaite, also below is the job configuration where am facing the issue. 

Please try to save and modify the config more than 3 times (after the complete config was saved, try modifying something on it).

markewaite, Appreciate your help here..
are you able to reproduce it? is there anyway to resolve this? this is kind of blocker. Could you please help.

I'm able to reproduce it based on your screenshot. It is a known issue JENKINS-64639 with the join plugin. A change has been included on the master branch of the join plugin. I verified that the change allows me to save the configuration of the job that was previously failing to save in join plugin 1.21

Your alternatives are:

• Use Jenkins 2.263.4 instead of Jenkins 2.277.3, accepting that there are known security issues fixed in Jenkins 2.277.2 that aren't available in Jenkins 2.263.x. Since you've been running the previous version for over two years without updating, I assume that is not an issue in your installation
• Try a pre-release of the join plugin that I've attached as join.hpi . It was built from the master branch
• Stop using the join plugin and convert your jobs to Jenkins Pipeline

Thanks So much markewaite, will try one of this work around and will update you.

we are good now, thanks markewaite

I was facing the same issue searched a lot and finally this solution helped me fix the issue. I used provided join.hpi.

Thanks markewaite.

vermavina69 or 1996phani it would be nice if you were willing to adopt the plugin.  We have a series of video tutorials on plugin adoption that would allow you to adopt the plugin, make a series of changes, and then release a new version of the plugin.

Hello markewaiteWaite, will go through the tutorials. thank you..

Sure markewaite I will go through the tutorial. Thanks!