Reviewer dropdown fails to return user list

[BrianKrohn]

When starting to create a pull request in Bitbucket 5.5.0, the reviewer list hangs. Logs indicate Null Pointer Exception in com.monitorjbl.plugins.UserUtils.getUserDisplayNameByName.

Log:
2017-11-21 07:46:33,768 WARN [http-nio-7990-exec-18] usernamehere @S1AW2Kx466x167256x0 11blfdc 192.168.50.140:52732,0:0:0:0:0:0:0:1 "GET /rest/api/latest/projects/DEVOPS/repos/axis/pull-requests/77/merge HTTP/1.1" c.a.s.i.h.r.DefaultRepositoryHookService [DEVOPS/axis[763]] Error calling com.atlassian.stash.internal.plugin.legacy.MergeRequestCheckAdapter.preUpdate (com.monitorjbl.plugins.pr-harmony:mergeCheck) java.lang.NullPointerException: null at com.monitorjbl.plugins.UserUtils.getUserDisplayNameByName(UserUtils.java:40) at com.monitorjbl.plugins.PullRequestApproval.missingRevieiwersNames(PullRequestApproval.java:50) at com.monitorjbl.plugins.MergeBlocker.check(MergeBlocker.java:39) at com.atlassian.stash.internal.plugin.legacy.MergeRequestCheckAdapter.preUpdate(MergeRequestCheckAdapter.java:33) at com.atlassian.stash.internal.plugin.legacy.MergeRequestCheckAdapter.preUpdate(MergeRequestCheckAdapter.java:14) ...

Let me know if you need more from the log. I cut the full error short.