Some time ago we noticed a bug in the Google Merchant center system in which Google randomly removes access in the GMC after activating the CSS program. Google is not correcting this bug yet, so we had to come up with a solution.
If you have an email in the Merchant center that ends with @yourcompany.com, it can be removed. We do not yet know when and why Google removes the access after activating the CSS program, and we have not received any explanation directly from them.
Together with our clients, we came up with a solution. Several clients had their personal email in the Merchant Center, it was an @gmail.com account and of course, it remained there even though other access emails were removed.
Therefore, before we activate the CSS program, you should: