wp_mail has been declared by another plugin or theme

Hi, Many support tickets to the Post SMTP plugin opened because of the error in the title. Quick intro: WordPress allows me as a developer to overwrite the internal mailing flow managed by a function called: wp_mail. this function and a lot more like her (that can be overwritten) are inside a file called: pluggable.php. … Read morewp_mail has been declared by another plugin or theme