Symptoms

I'm trying to create an Exchange Mailbox through a K2 workflow but it fails. The Exchange EWS URL can be resolved with Internet Explorer. The configuration Analysis doesn't show any failures or warnings. There are errors in Event Viewer:

0 Exchange service failure: Cached EWS URL is not valid or server unreachable.

10702 An error occurred in the Exchange Administration service instance. Exception has been thrown by the target of an invocation. Cached credentials for DEVadministrator could not be found. You can cache credentials via the 'User Settings': 'Single Sign-On' area in K2 Workspace.

10702 Retrying the Exchange Administration service instance as the K2 service account did not resolve the issue. Exception has been thrown by the target of an invocation. Cached credentials for DEVadministrator could not be found. You can cache credentials via the 'User Settings': 'Single Sign-On' area in K2 Workspace.

28083 ServerEvent: Message: Exception has been thrown by the target of an invocation. Cached credentials for DEVadministrator could not be found. You can cache credentials via the 'User Settings': 'Single Sign-On' area in K2 Workspace. ServiceName: Exchange Administration ServiceGuid: 55627c31-e7f0-41f7-8ef6-d916f8284e68 InnerExceptionMessage:

 

Diagnoses

We ran the ConnectionStringEditor.exe tool found in this location: C:Program Files (x86)K2 BlackpearlHost ServerBin

We checked the EWS connection strings included the correct username and password for the Exchange login details (for the K2 Service account), even switched the Autodiscover option on and off, no change.
 

Resolution

It turns out this issue was caused by not enough system resources on the virtual machine. After spreading the Virtual machines to two different harddrives, allocate more System resources and restarting all Systems, everything works as expected, so it was a Hardware issue.