During migration from/to G Suite, you have noticed the following error:
“invalid_grant”, Description:”Invalid JWT Signature.”, Uri:”””
The p12 key uploaded to the platform is invalid or expired.
1. Check if you created a key for the corresponding service account ID (entered in your source connector).
2. Most probably your key has expired. Just to generate a new one and update it on the platform.
Refer to this article How to create an admin account for Google migration?