The NTHW site reiles on open source forum software from SimpleMachines. The Forum is periodically updated when security patches are released. There was an update earlier this week, and the forum itself is working normally. The update may cause you to need to login to re-establish your user identity.
There is an issue with login redirection if you visit the site through a www address. In this case your user credentials may not correctly register with the site. It may create some error messages.
If you have browser shortcuts, to NTHW, please amend these to exclude any www as part of the address.
Use of https://nthwgaming.co.uk should resolve any login issue.