Error: wp_mail has been declared by another plugin or theme


thanks for your great plugin that makes monitoring our wordpress installations much easier!

Unfortunately, after updating to version 4.1.5 today another plugin (Post SMTP) is currently not able to use the WordPress function wp_mail throwing the following error message:

wp_mail has been declared by another plugin or theme, so you won’t be able to use Postman until the conflict is resolved.
More info that may help - /httpdocs/wp-includes/pluggable.php:171

See also:

Disabling all e-mails in the ‘Email Settings’ of MainWP did not help. On the other side, disabling MainWP did indeed help sending mails through Post SMTP again. All other plugins are disabled.

We were not able to locate the wp_mail name conflict in the MainWP plugin. So we are unsure what causes the error.

Wordpress: version 5.7
Post SMTP: version 2.0.22
MainWP: version 4.1.5
PHP: version 7.4.9

Thanks a lot

Hi Karl,

thanks for reaching out and reporting this.

The conflict has been fixed and included in the MainWP Dashboard

Hi Bogdan,

Post SMTP works after disabling and reactivating the plugin in Wordpress.

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