Microsoft office 2003 outlook problem

Emailing was working fine until approx. 3 wks ago when friends telephoned to tell me that they had replied to my emails but received "email undeliverable." bounces.
I can send NEW mail, sen Replies and Forward - all ok
I can receive NEW mail and receive Forewarded mail ok but not Replies.
I can receive NEW, REPLIES and Forewarded mail in my ISP's Webmail.
My ISP says there is nothing wrong with my email account with them and that it must be with OUTLOOK.

I run Windows XP with Microsoft Office 2003.

Help appreciated

Bumlingbill

 

It may be that you have the wrong REPLY address configured in Outlook.

 

many thanks for the reply. I've looked in OUTLOOK but can't see where there is an option to add/change a reply address. - my outgoing is POP3 and incoming is SMTP.
Am I looking in the wrong place?

Your menu box just came through! - my internet is slow! I checked mine and it is correctly configured

 

Do the folks that are trying to reply to you get a bounce message?????

 

My ISP Help Centre has confirmed that it can receive my emails, and successfully reply to them. I receive those replies in webmail.

However, replies from other people do not get down to me from my server!.

Further checks with the Help Centre indicate that my problem may NOT be with OFFICE 2003 OUTLOOK but with my ISP-

I set up a yahoo email address and sent myself an email from the problem address to the yahoo address - it arrived ok so I replied to it from the yahoo address - it never arrived in either my ISP's webmail or in OUTLOOK! I followed it up with a NEW email from Yahoo. This came through to OUTLOOK / webmail very quickly.

I have now been back onto my ISP and they are now escalating the problem to the 3rd line support!

I'm not sure that anything else can be done until they report back (24/48hrs).

Thanks for the help - sorry if I confused you all!