Would you check your job and global configuration setting first against the release note? 

It's a huge change from v2.2.2 to v3.x. 

Or, would you share the configuration image for me? 

The configurations are proper. PFA.

thanks, would you also provide the global remote host configuration? 

Yes, we use it Jenkins A. There we will be providing a "Display name" and "Remote Jenkins URL", then the same will be reflecting under "Select a remote host" inside the Server Info for the job.

dineshkumar_n, you should check your remote server configuration.

If the URL can be correctly parsed, it's no way that url.getHost() throw NPE. 

String addr = server.getAddress(); 
if (addr != null) { 
  URL url = new URL(addr); 
  Semaphore s = hostLocks.get(url.getHost());  <---- line 385

By the way, in the 3.x.x releases, almost every release has some configuration changes.

Although most of them are adding fields to the original configuration, you should still check your setting. 

I have validated the configurations and all are proper. When i executed the build i am facing the below issue without a configuration change :

fail to accquire lock because of timeout, skip locking...
CSRF protection is disabled on the remote server.
fail to accquire lock because of timeout, skip locking...
Connection to remote server failed [404], waiting for to retry - 10 seconds until next attempt. URL: https://<Jenkins_URL>/view/All/queue/item/81305/api/json/,
parameters: Retry attempt #1 out of 5
Connection to remote server failed [404], waiting for to retry - 10 seconds until next attempt. URL: https://<Jenkins_URL>/view/All/queue/item/81305/api/json/
parameters: Retry attempt #2 out of 5
Connection to remote server failed [404], waiting for to retry - 10 seconds until next attempt. URL: https://<Jenkins_URL>/view/All/queue/item/81305/api/json/,
parameters:
Retry attempt #3 out of 5
Connection to remote server failed [404], waiting for to retry - 10 seconds until next attempt. URL: https://<Jenkins_URL>/view/All/queue/item/81305/api/json/,
parameters:
Retry attempt #4 out of 5
Connection to remote server failed [404], waiting for to retry - 10 seconds until next attempt. URL: https://<Jenkins_URL>/view/All/queue/item/81305/api/json/,
parameters:
Retry attempt #5 out of 5
ERROR: Remote build failed with 'ExceedRetryLimitException' for the following reason: 'Max number of connection retries have been exeeded.'.
ERROR: ExceedRetryLimitException: Max number of connection retries have been exeeded.

BTW, in the error "view/All/queue/item/81305/api/json/" is automatically getting added. If that is added in URL the same path will not be present. Kindly can you provide your inputs.

fail to accquire lock because of timeout, skip locking... <— this line wasn't related to your problem

Connection to remote server failed [404], waiting for to retry - 10 seconds until next attempt. URL: https://<Jenkins_URL>/view/All/queue/item/81305/api/json/, <--- this line told the problem,

Please check your remote server URL in either global configuration & job configuration, and check your job name or URL  as well, 

the segment "view/All" is definitely added by some mistakes and definitely not auto-generated by this plugin. 

I could almost 99% recognize this issue as a man-made error ...

Be more specifically, your job URL should be in http://*some_jenkins_host*/job/*some_job_name*/ instead of directly copy the URL with view in it.

Without the specific job URL, there's no way to 100% tell an accurate job name.

So, please,

use the url format i gave,

or just give a job name along with the remote server config whose URL should be http://*some_jenkins_host* .

Hope this will help you out.