We are having the same issue here. It began about 10 days ago. Our gmail got reinstated 3 days later, but it happened again tonight.
We are not sending bulk emails. The Forms filled out from our wp site go to “gmail #1” and are found in the sent folder of thet email, and being forwarded to “gmail #2”.
Only 1 of the 2 gmails got suspended. The primary one did NOT. I can see the completed forms in the “sent” folder of the primary email. The gmail they are being sent 2 is the one that keeps getting suspended.
I do NOT have a forward or filer on the gmail either.