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Thain Esh Kelch · May 7, 2009, 03:48 PM

So, my girlfriends PC is making problems. Thunderbird on Windows XP, set up with her Gmail and Hotmail. She's using our ISPs outgoing server (Port 25), which works fine on my Mac. But for some reason, whenever she tries to send an email, she gets the error "<[email protected]>: Sender adress rejected: Invalid Sender Domain. Control receiving adresses and try again." - Of course the receiving emails are correct. I've also tried Gmail's own outgoing server, but I believe the port its using is being blocked by our ISP (I think this is normal in Denmark) - But nevertheless, it gives the same error.

Any ideas?

seanc · May 7, 2009, 04:09 PM

Have you tried authenticating with your outgoing SMTP server? You'll probably need to use the account details your ISP gave you.

Thain Esh Kelch · May 8, 2009, 02:50 AM

Originally Posted by seanc

Have you tried authenticating with your outgoing SMTP server? You'll probably need to use the account details your ISP gave you.

You mean access the outgoing server with login/password? We never do that with ISPs here in Denmark, and it works without login on my Mac.

Big Mac · May 8, 2009, 07:04 AM

Strange problem. Have you tried a different client?

Thain Esh Kelch · May 8, 2009, 07:08 AM

Actually, she also used the Windows Live email client, and while it did send emails to some receivers, others it didnt want to send to, at random.. It was quite strange really.. It insisted that the receiving adresses were also wrong!

Now that you mention it, I'm going to try several adresses and see what happens.

besson3c · May 8, 2009, 09:17 AM

If you do not authenticate to your SMTP server chances are they have configured it to only permit sending mail with from headers that match their domain. This prevents compromised PCs on their network from sending mail from other domains with the ISP's envelope address, getting their SMTP server put on blacklists.

You should find an SMTP server that allows authentication, and sending of messages with any from address. If you can't contact other SMTP servers on port 25, try the standard submission port which is 587.

Thain Esh Kelch · May 8, 2009, 09:26 AM

But, I use my Mac for sending Gmail/Hover.com/Hotmail throught my ISPs SMTP server, and it works fine? (If I understood you correctly, lots of new words).

besson3c · May 8, 2009, 09:40 AM

If you can really send mail via non ISP domains without authenticating, I would get off using their SMTP server anyway. It is probably blacklisted all the way between here and China if all that is necessary to send mail with their server is to be on their network, unless they have full control over the potentially compromised machines on their network.

That being said, if you can do this on your Mac there is probably just a difference in your client's configurations. Mail is mail, it is platform agnostic.

Thain Esh Kelch · May 8, 2009, 09:45 AM

Its actually normal for danish ISPs to block everything but port 25, when it comes to email. I guess they just monitor the amount of data send...

But I guess I'll just give up on her email.. She's going to buy a new one in the summer anyway, and she's still trying to figure out if it should be another Windows, or a Mac instead.