Hi there!
It seems not related to our product. But related to the database!
From when you are facing this issue, and what you did lastly please let us know.
Also, you may check the following link for suggestions:
https://stackoverflow.com/questions/10316138/joomla-session-automatically-logs-out-no-content
However, I have checked your backend and found out you have templates from both Helix Ultimate and helix3 framework.
https://prnt.sc/15ud8hc
Please keep templates from only one framework as they are different in many criteria which may cause issues.
Best Regards