SM issue: Session timeout and Maximum active logins exceeded

Hi Experts,
we had a stable application till yesterday. Today suddenly we had all our users reporting the following issue:

Two errors -

1. After they try to save a call, update history or if the session is open for about 30 seconds, they received the below error:
"You have been logged out due to session timeout."

2. Once user tries to login again:
"Login failed. Maximum active logins for this user exceeded."

Any ticket they were working on, gets locked

We are using SM9.30. We killed the sessions for users and that worked but it kept recurring. Any idea what could have caused this issue or any workaround?