When you are using Exchange online for sending emails, Exchange online has a limit of 30 email messages per account per minute. This is causing the K2 Server to continuedly retry sending the emails/ K2 Workflow email step. This builds up to the point where all K2 Workflow threads are exhausted resulting in not being able to connect to the K2 Workflow server anymore.
If you are encountering this behavior where your K2 Workflow threads are exhausted because of excessive emails being sent through to Exchange online, we recommend that you specify the number of retries.
And we also recommend you to check whether you would like the K2 Workflow to go into error state after the retries all fail or if you would like the K2 Workflow to continue.
These settings are defined in the connection string for the EWS destination.
Edit the ConnectionStringEditor.exe found in the Host ServerBin folder and then select ExchangeWebservicesDestination (username).
The fix is available in:
- K2 Five (5.4) Fix Pack 48.
- Ensure you have the correct K2 version and/or Cumulative update installed. See KB001893 to see what Fix Pack level you have installed.
- Download the latest Fix Pack using the links in the table above for the version you require.
- Install the Fix Pack to apply the fix.
- It is recommended to clear browser cache and refresh the page.