Symptoms

К2 host server logs contain loads of errors similar to this one:
"Error","General","28083","ExtenderExecuteError","ProcessInstance.HandleException","28083 ServerEvent: Message: “The request channel timed out while waiting for a reply after XX:XX:XX. Increase the timeout value passed to the call to Request or increase the SendTimeout value on the Binding. The time allotted to this operation may have been a portion of a longer timeout.”
 

Diagnoses

Based on this message we can infer that possible some running process uses custom WCF service which is registered as a Service Object and for some reason started take more than 1 minute (default timeout) to respond.
It is necessary to find out what kind of service object generates time out errors and investigate opportunities to improve its response time. If there is no way to address response time, then consider possibility to apply a coldfix which is available via K2 support request, which will allow to set increased timeout value, but in any case it is necessary to check which service object gives you this error and what it does.

 

Resolution

Identify which Service Object gives you time out errors and check if response time can be improved. If there is no way to improve response time contact K2 support to request the coldfix which allow to set increased time out configuration.