If you find Yahoo Mail isn't syncing, you should first ensure that you have a reliable internet connection. Follow the various methods mentioned in this post if that's not helping. If the problem occurs due to a low Yahoo Mail server, check its status on downdetector.com. Another reason can be the incorrect Yahoo Mail sync settings. So, ensure that you have correctly configured the sync settings and have turned the sync on. Further, disable the security program on your device and check if the issue is resolved. Moreover, turn off the Windows Defender Security Center or delete your Yahoo Mail account from the device and add it again.
See also – Create Signature in Yahoo Mail , Yahoo Mail not working properly , Why Yahoo Mail Not Updating
