K2 uses TCP/IP ports to communicate with different servers. There is a default range that windows server allows access too and if that range is exceeded new connections cannot be opened. In addition too that windows server also leaves all tcp connections open for a default length of time before closing them meaning it is possible to have an open connection that is not in use which in turn makes it easier to hit the upper limit. If K2 starts reaching that limit, timeouts could be experienced. One of the more common presentations of this is an error to the effect of:

10032 SmartObject Server exception source: SQL Exception Connection Timeout Expired. The timeout period elapsed during the post-login phase. The connection could have timed out while waiting for server to complete the login process and respond; Or it could have timed out while attempting to create multiple active connections

To attack this you can manipulate the default values in the registry (make a backup first). Either increase the number of connections allowed or decrease the time connections stay open or some combination of the two.

The following MS Kb link explains the process:
https://support.microsoft.com/en-us/kb/196271