Best Guess:
As a large number of emails gets created within a very short span of time, Gmail's security algorithm detects this as an anomaly and temporarily suspends the activities of the same to protect the system.
It has also been noticed once in a while, the errors related to "Too many requests" and errors with Status code 421 from Gmail (SMTP)
Best Guess: As a large number of emails gets created within a very short span of time, Gmail's security algorithm detects this as an anomaly and temporarily suspends the activities of the same to protect the system.
It has also been noticed once in a while, the errors related to "Too many requests" and errors with Status code 421 from Gmail (SMTP)