When trying to forward an email to someone else or even trying to send a newly made email Outlook Express would give an error ,the weird thing was that it was a blank error with no error code.
The first thing to check is if the SMTP server is correct in the account options by going to Tools ,Accounts ,Mail tab selecting the email account and choosing properties ,go to servers tab and make sure the SMTP information is the correct information that was given by the ISP.
If all is correct then what you can then do is what worked for me many times which is create a new Outlook Express Identity.
First you must backup your email address and address book contacts.
Go to Tools ,Accounts ,Mail tab ,select your email address then on the right hand side click on the Export button ,select the destination and give it a name(keeping the extension .iaf).
If you have many email addresses then you have to do this for all of them.
Backing up the address book is very similar, click on the Address book tab(it should be next to the Send and Receive icon)once open click on File ,Export then choose address book(wab).
Select the destination and give it a name .
Once all this is done we can create a new identity.
On the File menu, click Identities, and then click Add New Identity ,type a name for the identity and click on OK.
When prompted say Yes to switch to the new identity, click Cancel to close the New Account wizard. If you are prompted to import settings or messages, select “Do not import at this time” or Cancel.
Now we are going to import the email address we exported.
Click on Tools ,Accounts ,Mail then choose the Import option on the right hand side and import the saved .iaf file.
the same thing must be done for address book contacts ,click on the address book icon then File ,Import ,Address Book(wab) and choose the location of the file and import.
Finally import your messages from the old identity ,on the File menu, click Import, and then click Messages, Select Microsoft Outlook Express 6 from the list of programs, and then click Next.
Then select the name of the Identity to import, and then click OK
The repair has now been done.
If you still get an error try to repair Outlook Express;
http://support.microsoft.com/kb/318378/en-us