Yes, until recently it worked fine on all businesses with different email providers but now with whatever setting it does no longer. Hence my alert to @Lubos on this. The email providers even gave me their own server rather than domain deviants but to no avail, so deductive reasoning puts it in the corner of some code change of the SMTP module in Manager, maybe even through an auto-update of the framework elements. I sincerely hope this gets looked into and resolved soon.