Have you disabled EasyWP SMTP or completely deleted it? If you’ve deleted it and it still shows the old from address, most likely some database entries are leftover. To fix:
- Depending on how you’ve setup Post SMTP mailer, try changing the From address details in this plugin’s settings
- Manually change the From address in WordPress using filters in
functions.php
. See method 3 at this link
Please note that this doesn’t remove any database entries created by the EasyWP SMTP (if any).