Some addresses I mail to get a mail undeliverable report. However if that person mails me and I use reply they get it okay. Is thsi na virus my AV program finds no problems on a scan
DS's tip is correct. The chance of a virus is almost zero in your case, especialy if you recognize the returned content.
You can also take a look at any e-mails you received from those trouble addresses and get the correct addresses from there. That way, you'll don't need to receive any new messages.
Electro
August 2012
Would not think virus, Check the address you use, make sure that you have a '.' not a ',' where needed, or when you get one from them, re copy the address, into where you keep them
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Try fixfault.com to fix email.