There is steps for How to fix G Suite email when not receiving emails?
You can try the following troubleshooting measures to fix G Suite email when not receiving emails:
1. Check for issues with your internet connection first of all.
2. Your device and your G Suite account must be in sync with each other.
3. Check if the incoming messages are not going to your trash. If so, find and remove the filter that is leading to this problem.
4. Always use compatible browser.
5. Make sure you have activated email in the Google Admin console.
6. Ensure that your MX records are configured to point to Google’s servers.
7. Make sure that the problem is not from the sender’s end.