Did you end up with a session timeout message while trying to create a NetSuite Connection using Cloud Extend Gmail beta? Here are possible reasons why you might end up in a session timeout.
Symptoms
Cause
Workaround
Symptoms:
Connection Creation flow gets halted with a session time out during the Three-Step Authentication flow.

While creating a new NetSuite connection using the app, you might end up in a session time out screen, not being able to proceed with the connection creation.
Cause:
One of the possible reasons for the connection creation process to get halted and a timeout is reached due to the fact that you may have accidently double clicked on the 'Allow' button while providing permission . This would end up the whole connection creation process to stuck and a time-out is reached.
You may also end up in the same situation if you had kept your 'Three-Step Authentication' popup unattended for a longer time also.

Workaround (Make sure you click on 'Allow' button once):
If your connection creation process gets timed out, try steps below;
Close the already opened 'Connection Creation' pop-up
Start creating a connection again via 'Connection Creation' menu in the app.
Make sure to complete the connection creation process in one go.