Massive spam problem with phpmailer

First off, check scan your site. These plugins can help:
Exploit Scanner
https://www.ads-software.com/plugins/wordfence/

Here is an another online scanner to check for exploits and malware: https://sitecheck.sucuri.net/scanner/.

Hi,

I tried both of those and nothing came up. The server is still send about 1000 emails per hour when all plugins deactivated.

I really don’t have a clue here!

You may want to contact your hosting provider and discuss the situation with them

Thanks for your help – we finally tracked down the errant script and deleted it. All back to normal now ??

Was the script something that was uploaded to your wordpress files? If so you will need to determine how this happened to prevent a repeat.

Um … (this is the embarrassing bit) … it was in functions.php. We were trying to change the way emails were formatted and messed it up. :/

Lesson learnt!

Glad you got it sorted ??