1.Please make sure that your email server allows emails from the server smtp.emailsrvr.com
Once you make the change, that will fix the issue
2. If you want to verify that it's an email issue specific to your email server, you can edit the approver user account and change the email address to a gmail or any other personal email address.
3. Then make the edits and test if the approver gets the email notification in the new email address.