we were running into an issue with memory exhaustion in our cache server; when this happens, through a variety of unlucky coincidences, the first thing the cache server decides to evict is user sessions, causing you to get logged out, and then the server can't find a place to store your session, meaning you can't log back in.
for the time being, this issue was resolved by migrating to a server with more memory and restarting the application. we've also got a series of better, longer-term solutions planned.
longer-term fixes
- we believe there's an issue with background processing leaking objects into the cache which we're already deploying a hotfix for.
- we're going to change the application to break up the data currently stored in one monolithic cache to use different caches for different types of data, hopefully reducing the impact of cache memory exhaustion issues in the future.
sorry for the inconvenience, and thanks for using cohost 
