logs:
{{Setting origin to git@gitlab:gitrepo.git
Fetching origin...
FATAL: Failed to recompute children of Sync Branches
hudson.plugins.git.GitException: org.eclipse.jgit.api.errors.TransportException: git@gitlab:gitrepo.git: Failed to connect
at org.jenkinsci.plugins.gitclient.JGitAPIImpl.fetch(JGitAPIImpl.java:680)
at jenkins.plugins.git.AbstractGitSCMSource.retrieve(AbstractGitSCMSource.java:171)
at jenkins.scm.api.SCMSource.fetch(SCMSource.java:143)
at jenkins.scm.api.SCMSource.retrieve(SCMSource.java:219)
at jenkins.scm.api.SCMSource.fetch(SCMSource.java:169)
at com.github.mjdetullio.jenkins.plugins.multibranch.AbstractMultiBranchProject.computeChildren(AbstractMultiBranchProject.java:582)
at com.cloudbees.hudson.plugins.folder.computed.ComputedFolder.updateChildren(ComputedFolder.java:151)
at com.cloudbees.hudson.plugins.folder.computed.FolderComputation.run(FolderComputation.java:106)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:410)
Caused by: org.eclipse.jgit.api.errors.TransportException: git@srv-lab-t-401.zhaw.ch:cyclops/cyclops-prediction.git: Failed to connect
at org.eclipse.jgit.api.FetchCommand.call(FetchCommand.java:139)
at org.jenkinsci.plugins.gitclient.JGitAPIImpl.fetch(JGitAPIImpl.java:678)
... 9 more
Caused by: org.eclipse.jgit.errors.TransportException: git@srv-lab-t-401.zhaw.ch:cyclops/cyclops-prediction.git: Failed to connect
at org.jenkinsci.plugins.gitclient.trilead.TrileadSessionFactory.getSession(TrileadSessionFactory.java:54)
at org.eclipse.jgit.transport.SshTransport.getSession(SshTransport.java:136)
at org.eclipse.jgit.transport.TransportGitSsh$SshFetchConnection.<init>(TransportGitSsh.java:262)
at org.eclipse.jgit.transport.TransportGitSsh.openFetch(TransportGitSsh.java:161)
at org.eclipse.jgit.transport.FetchProcess.executeImp(FetchProcess.java:136)
at org.eclipse.jgit.transport.FetchProcess.execute(FetchProcess.java:122)
at org.eclipse.jgit.transport.Transport.fetch(Transport.java:1138)
at org.eclipse.jgit.api.FetchCommand.call(FetchCommand.java:130)
... 10 more
Caused by: java.io.IOException: There was a problem while connecting to srv-lab-t-401.zhaw.ch:22
at com.trilead.ssh2.Connection.connect(Connection.java:818)
at com.trilead.ssh2.Connection.connect(Connection.java:687)
at com.trilead.ssh2.Connection.connect(Connection.java:587)
at org.jenkinsci.plugins.gitclient.trilead.TrileadSessionFactory.getSession(TrileadSessionFactory.java:29)
... 17 more
Caused by: java.io.IOException: Key exchange was not finished, connection is closed.
at com.trilead.ssh2.transport.KexManager.getOrWaitForConnectionInfo(KexManager.java:93)
at com.trilead.ssh2.transport.TransportManager.getConnectionInfo(TransportManager.java:230)
at com.trilead.ssh2.Connection.connect(Connection.java:770)
... 20 more
Caused by: java.io.IOException: Cannot negotiate, proposals do not match.
at com.trilead.ssh2.transport.KexManager.handleMessage(KexManager.java:405)
at com.trilead.ssh2.transport.TransportManager.receiveLoop(TransportManager.java:777)
at com.trilead.ssh2.transport.TransportManager$1.run(TransportManager.java:489)
at java.lang.Thread.run(Thread.java:745)
Finished: FAILURE}}

The same git repository and credentials works fine for a single maven project. Could it be because private gitlab configurations? unfortunately I don't have an access for gitlab server. but as it works for single maven project and doesn't for multi branch I consider it as a bug.

Thanks a lot for a help!
best regards,
Oleksii