admin error login

[pocttopus]

I don't know where to open this topic so please move to right board if this is not proper place. Thanks.

I have these errors:

Code Select Expand

Error
Type of error
Critical
Error message
Administration login attempt!
Referrer: https://xxx/index.php?action=admin
User agent: Mozilla/5.0 (Android 11; Mobile; rv:90.0) Gecko/90.0 Firefox/90.0
IP: xxx
URL of page causing the error
https://xxx/index.php?action=admin
Backtrace information

    #0: adminLogin()
    Called from /home/xxx/public_html/Sources/Security.php on line 86
    #1: validateSession()
    Called from /home/xxx/public_html/Sources/Admin.php on line 457
    #2: AdminMain()
    Called from /home/xxx/public_html/index.php on line 187



Just for a reminder, I am already opened issue about login and registering a new member in this topic:
https://www.simplemachines.org/community/index.php?topic=578210.0

I can login ONLY with Basilisk browser which is using XUL.
All other browsers (firefox, chrome, edge, opera, vivaldi) still cannot login nor register on my forum.
How can I solve this?
THanks!