Have you tried changing the receiving address to a different mail client to see if messages come through?
Note, before you make any of the changes below, you might try logging into your file manager, opening the mail folder, then selecting “New”. Sometimes rejected messages will be saved there.
Next, I would try installing the plugin Postman SMTP so that an actual email account will be sending website mail instead of WordPress’ standard PHP mail function.
In my experience, this problem was combination of using shared hosting (and the website’s IP getting listed in Composite Blocking List) combined with Outlook’s prodigious spam filters. Upgrading to a dedicated IP and SSL may be something to consider as well.
Here’s how to set up Postman SMTP after installing it: https://vimeo.com/128589255.
Hope this helps!
M
Thank you @thisisntmary for pointing me towards Postman!! It solved my issue. For some reason, the simple contact form in my footer was sending just fine, but a detailed questionnaire abruptly stopped sending. Now I’m routing through Gmail and all is good. Cheers 🙂
