bt internet addresses don't receive my email

Since installing Avast anyone with the address xxx@btinternet.com doesn’t receive my mail via Outlook but all others do.
Any help is appreciated.

B

avast does not block or filter any email address.
Or you’re sending a lot of identical emails and the avast Outlook Heuristics is alerting you (and blocking the email to be sent) or any spam/filter in your computer (or in theirs) are blocking it.

Are you using Outlook or Outlook Express?

If you are using Outlook are you using the Internet Mail provider of avast or the (preferred) Outlook plugin?

Using OUtlook and both the mail and outlook plugins are enabled. Help please! My brother doesn’t receive my mails. Every other isp address receives no problem.

If the message has been saved by Outlook in the “Sent” messages folder then it has received a positive confirmation that the message you sent has been received by the server of your email provider. From then on the delivery of the mail is the responsibility of your email provider and has nothing to do with your email configuration or avast.

Please ask your brother to check his email via the Web interface that is almost always available these days and double check that - for whatever reason - it is not ending up in his spam folder. If it is and he receives your email in a POP email client then he will never see your messages because POP clients cannot download mail that ends up in the spam folder on the mail server (that’s the rules of the POP protocol).