Your Salesforce Session Settings must be equal or greater to the Expiration for Open in Word settings you select in Conga CLM Setup.
You can configure the session timeout settings for the Open in Word feature.
Warning: The document will be locked for other users for the duration of the time you select once the document is opened in Microsoft Word for editing.
Within Salesforce, navigate to Conga CLM Setup.
Click View Redlines in the left menu.
Select one of the session timeout options the available options are:
1 Hour
2 Hours
4 Hours
8 Hours
For example, if you select 4 hours, your Open in Word session will not time out for four hours.
Note: If the Open in Word session expires and you try to Save from Microsoft Word, the upload will fail and you will receive an error message. You must close the document and start a new session.