It appears that the root of this problem was none other than the troublesome “emailpouble,” similar to the case mentioned in Problème réception et envoi de mails - #3 by vincentux. Regrettably, my grasp of the French language is far from proficient, rendering this topic elusive amidst my English search terms. Nevertheless, I’m relieved to inform that the issue has been successfully resolved. For those facing a similar predicament, consider this post a parallel guide in English. To rectify this ordeal, the recommended course of action is to eradicate the culprit – “emailpouble” (or just remove it in plain English).