If users exceed an email sending limit, they’ll get an error message, such as:
You have reached a limit for sending email.
You reached a Gmail sending limit.
You exceeded the maximum recipients.
If you exceed the limits, your account will be blocked for 24 hours. However, users can still access their Google Workspace account, get incoming emails, and use their other Google services. After this suspension period, sending limits are reset and users can resume sending mail.
Gmail sending limits
You can send 500 emails per day (for trial accounts). And with paid services like Google Workspace, you can send over 2,000 emails per day.
Sending limits are different if your organization uses the SMTP relay service to route outgoing mail through Google.
Quotas might be different if you're using Google Apps Script.
The Google Groups for Business service has its own Gmail message and posting limits.
(Applies to both internal and external recipients)
These limits are also shown on: Gmail sending limits in Google Workspace