The following error is appeared when connecting to the panel:
MySQL query failed: Unknown column '' in 'where clause'
db_query(string 'SELECT login, type, ip_address, ip_dual_stack FROM sessions WHERE sess_id=""')
MySQL configuration file /etc/my.cnf contains following setting:
With ANSI_QUOTES enabled, you cannot use double quotation marks to quote literal strings, because it is interpreted as an identifier.
Comment this line or delete it in /etc/my.cnf and restart mysql server: