If you’re logged in, or having issues logging in, where you get booted back to the main login page, and your:
/var/log/directadmin/error.logshows this error
Rejected session for user admin because IP (1.2.3.4) doesn't match session file (5.6.7.8)but both IPs are yours, that’s likely due to some IP rotating which can happen with proxies, mobile devices, or when a client connection uses both IPv4 and IPv6 interchangeably.
As this IP check is not commonly done with sesion based login, it is considered extra level of security, so you can disable it if you need to by adding to your /usr/local/directadmin/conf/directadmin.conf and restarting directadmin.
disable_ip_check=1