Intermittent login issue

Running OF 3.8.2 on CentOS 6.6. For user authentication, server is hooked up with LDAP service of a Zimbra mail server. All client are on Spark 2.6.3 on different platforms (Windows, Linux, Solaris)

From few days, when we updated the OF server with yum update, we are facing the issue of logging into the OF. This occurs on intermittent basis for all users.

User see invalid user name and password error on an attempt, click ok and click Login button, After couple of tries, server accepts the same credentials and allow to login.

  • We have verified connectivity between OF and LDAP server.

  • /opt/openfire/logs didn’t provide much help here.

Can some one please suggest what could be the possibility here? And where to look at in order to find the issue.

Thank you.