Hey there, It seems the system is having some kind of issue with PHP. There’s nothing you can do about it. All we have to do is wait until the admin fixes it.
SquirrelMail is quite old software, and last time I checked they did not support PHP 8 in their stable version. They released a “snapshot” version that does support it and you could use, but you’ll have to install it by hand. But Softaculous typically only ships the latest stable version, not unreleased versions.
We do not have the IMAP extension enabled on our servers, so webmail software hosted with us will not be able to connect to most mail servers.