[ADMIN] Postgres will not allow new connections, suspended process, waiting error

We have a recurring problem where Postgres will not allow any new connections. Any connection already made keeps working fine. Every time this happens, we also have one suspended postgres.exe process that can not be cancelled. Also, we get the following error in the logs every minute: ‘WARNING:  worker took too long to start; canceled’.

We’re using Postgres 9.5 on Windows Server 2012 R2. Our original hypothesis was that there was something wrong with the autovac settings, but we copied the settings over from our other server that does not have this problem and still continue to have problem.