using GMAIL's Auto-configuration tool or did you do it manually and if so (either way) did you follow all steps here:
Since you are receiving GMAIL it is obvious you have set that option on the GMAIL site but since you can't send it is probably you never completed configuring your client (Outlook Express).
Do or check your Outlook Express GMAIL account for the following:
on the Servers tab
1. Enter 'pop.gmail.com' in the 'Incoming mail (POP3, IMAP or HTTP) server:' field.
2. Enter 'smtp.gmail.com' in the 'Outgoing mail (SMTP) server:' field. Click 'Next.'
3. Enter your Gmail username (including '@gmail.com') in the 'Account name:' field.
4. Enter your Gmail password in the 'Password:' field, and click 'Next.'
5. Place a check in the checkbox at the bottom of the Servers tab where it says 'My server requires authentication.'
6. Click the 'Advanced' tab.
7. Check the box next to 'This server requires a secure connection (SSL)'
8. under 'Outgoing Mail (SMTP).' Change the '25' to '465' in the 'Outgoing mail (SMTP):' field.
9. Check the box next to 'This server requires a secure connection (SSL)'
10. under 'Incoming mail (POP3).' Change the '110' to '995'.
11. Click the OK button and you should be done.
I've been having trouble configuring outlook express with my G-mail account. I followed the instructions in g-mail but with no success. When I go to outlook express the g-mail window comes on and asks for my password. I give it but it won't accept. I then get the following error message: ''There was a problem logging onto your mail server. Your Password was rejected. Account: 'pop.gmail.com', Server: 'pop.gmail.com', Protocol: POP3, Server Response: '-ERR [AUTH] Username and password not accepted. i19pf1150692wxd', Port: 995, Secure(SSL): Yes, Server Error: 0x800CCC90, Error Number: 0x800CCC92''. Strangely enough, I have been getting incoming g-mail to outlook express but am not able to send outgoing mail from outlook express. I would appreciate any suggestions.