While trying to post comments in an particular ISSUE (for some others it works) i get "Communication Breakdown" problem.
The only way to post a comment in such issues is to post the comment while resolving the issue and then i need to reopen.
Sometimes it helps if i remove temporary the issue from Sprint - but not always.
I've already checked https://confluence.atlassian.com/display/JIRAKB/JIRA+Links+Menu+Errors+due+to+Communication+Breakdown but did not helped.
I get no error in attlassian-jira.log
No error in apache error log.
in access log I get a:
xx.xx.xx.xx - - [16/Jul/2015:10:49:48 +0200] "POST /rest/api/2/issue/OPERATIONS-2914/comment HTTP/1.1" 400 110
xx.xx.xx.xx - - [16/Jul/2015:10:49:49 +0200] "GET /rest/quickwatch/1.0/notification/count/unread?_=1437036593681 HTTP/1.1" 200 27
xx.xx.xx.xx - - [16/Jul/2015:10:49:49 +0200] "GET /rest/scriptrunner/1.0/message?_=1437036593862 HTTP/1.1" 204 -