47 votesAndrew G commented
I have at least received this from Sophos Support:
You may run: sudo vi /var/aua/AuaConfig.pm then edit the value for $radius_timeout.
***Please be informed that it is not adviseable to edit this settings and Sophos Support is not liable if in case there's an issue happened after updating this settings.***
Doing this has stopped the timeout error but I haven't quite gotten it working, it only works when it's already cached the previous radius authentication