Hi,
Please check the below steps.
1. Check Email address in the Approval user setup is correct or not.
2. In your approval workflow the below step is present or not. Create notification Ideally it should be present.
3. Check the Email accounts page the account is setup up as default or not. Ideally it should be default.
4. Go to Job queue entries and check notification schedule job queue is error out or not?
if it is error out what is the error message?
If my answer was helpful to you, please verify it so that other users know it worked. Thank you very much
