Authentication error -- Session not found

Hello all,

I have Openfire version 3.9.3 and in the logs I found

org.jivesoftware.openfire.handler.IQAuthHandler - Error during authentication. Session not found in [c252bad6, 8cb4499b, 6435e8be, aee91f82, a561649, d70bb256, 4aca6db3] for key p623290@{company_name}/android

I count 89 of "Session not found in".

My questions are:

1) Is it possible to have any issues as long as those sessions errors increases?

2) How can I clean those errors? Tried by restarting Openfire and did not work

3) How many session can openfire handle?

Thank you,

George