Jira sync stopped working for new bugs or defects

Our Jira integration stopped syncing few days back for any new defects created in QAComplete or bugs created in JIRA.

Below are the messages we are seeing more often in the logs while some of the existing links get synced up but not in real-time:

• StatusCode:  (SecureChannelFailure) ResponseBody:
• StatusCode: 401 (Unauthorized) 

Melissa_Campbel had reported an issue earlier in March and things seem to be working and then more issues occurring recently in May.