Symptoms

During K2 for SharePoint registration phase, on prompt of K2 URL, when we entered a valid K2 URL, it displays error:

"A Web Service URL could not be found in the autodiscover results."
 

Diagnoses

Web Service URL SSL is missing in Environment Library. Turns out the Web Service URL and Web Service URL SSL environment fields need to exist for the autodiscover to work properly.
 

Resolution

Add Web Service URL SSL back to Environment Library and restarted the K2 blackpearl server.