Steps

1.Upgrade the zabbix from the version < 5.2 (4.4 in use case)

2.Try to login with superadmin user

Result

Fail to login with LDAP authentication type and guest permissions with internal type

Root reason founded in frontend code

/usr/share/zabbix/include/classes/helpers/CEncryptHelper.php

public static function updateKey(string $key): bool {
 return DBexecute(
 'UPDATE config'.
 ' SET session_key='.zbx_dbstr($key).
 ' WHERE '.dbConditionInt('configid', [1])
 );
 }

In case when configid !=1 into config table - query has not executing. If we change it in DB with the query

update config set configid=1;

Everything has working fine

But, we have to change this logic, and drop the hardcode condition  update query from a frontend for configid  filtering, because there is the only one row for configid - why to filter it?