BTinternet account not receiving from oneandone.com
Setting up a mailing list from our ionos based website involves it sending the invite email from the mailing list manager at email@example.com to each invitee. That address can't be changed and I can't see what it sends.
Everyone has got the invite except for any btinternet accounts which get nothing. Not in SPAM either. Have setup safe senders and added to contacts to now avail. Just spent 45 minutes with Ionos support but they don't understand where it's going either! Any ideas before I look for a different mailing list solution?