WP Mail SMTP stops working when I add my site IP to the Mailgun whitelist

[chuangzu]

Website URL

Taichielements.com

Error Message

WP Mail SMTP says 401 forbidden return message from Mailgun

Other Information

Test mail stopped working and website forms also ceased to function.

When I migrated my site to Infinity Free, I added the new site IP address to the Mailgun whitelist, which blocks all API and SMTP traffic from any IP other than the ones listed in the whitelist.
Looking at the Mailgun logs, it would appear that all activity with Mailgun ceased from this point forward.
If I remove all IPs on the whitelist - effectively disabling it - the forms and test emails start working again, I add the IP, and they stop.

Is there another IP or IP range, besides my actual website IP address, that I need to add to their whitelist so I can use my forms and benefit from their whitelist’s security?

[TiffanyLynch]

@chuangzu

another IP

If i remember correctly, the requests from your website here in IF to the outside internet is handled by another server. Try creating a php file in your htdocs directory with following code:

<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'http://checkip.amazonaws.com');
curl_exec($ch);
?>

Open it, and the IP shown is the one you would put in a whitelist. In my case, for a site hosted in 185.27.134.102, the requests to outside world is handled by 185.27.134.53.

[chuangzu]

Thanks for the info Tiffany.
I didn’t know what you meant by ‘open it’ at first and I tried to open it in file manager but you meant open it in your browser.