My wife and I both used to receive weekly emails from @cac.org in USA.
Recently her copy has stopped coming, but mine is continuing.
We wrote to cac.org and they tell me they send many thousands and their provider does not send individual letters giving the reason, they just get told it has not been delivered.
no address at @cac.org is in her spam box.
How do I restore the service which has been so good for many years?
First thing is to check the method of receiving messages is working.
How do you each receive these email messages? Do you both sign in to TalkTalk Mail at https://apps.talktalk.co.uk/appsuite and both of your mailboxes are on the new TalkTalk Mail platform?
If not what are your email domains - the bit after the @ in each of your email addresses - please don't post full addresses here though.
If one of you receives the messages then the emails aren't being blocked by network spam filters that can block bulk mailers if many people mark messages as spam instead of unsubscribing.
Check to see if there are any filter rules operating. For TalkTalk Mail - Menu > Settings > Mail / Email, select arrow > Filter rules. If there are any rules then disable them to test.
Pragmatically, if you're receiving the messages then you could set up a Filter rule to forward those messages to your wife's email address.
But check that the mailbox isn't full or corrupted by a stuck email and not receiving any new messages. Test by sending her an email to make sure it arrives ok.
I assume the sender is still sending her messages? Some will stop sending when the first message is bounced back as undeliverable.