Many users report that they encounter the “Gmail getting your messages” and “Gmail waiting for sync” error messages while trying to open the Gmail app. In this situation, the Gmail app on your device might become very slow. In some of these cases, you will not be able to send or receive emails as usual. To resolve the issue, make use of the simple methods given here to solve the issue of Gmail getting your messages waiting for sync.
Restarting the device you are using would fix minor glitches and errors. So, try this method to solve the syncing error on the Gmail app on your device. After you restart, check whether the issue is resolved. If yes, then you can stop here and start using the app as usual. If not, proceed with the next method.
In many situations, updating the Gmail app has solved the syncing problem on the device. Therefore, download the latest version of the app onto the device and use it. In case you are using an Android phone, try these steps: