ASP website issue: Error code

My website has been working no problem, then late yesterday the following error code came up: error '80040211' /customers/[login to view URL], line 1326 now we can't input or change account data. Everything else seems to work fine. I need someone who can fix this as quickly as possible. I've looked up the error code and this is what I found: "From what I've read error 80040211 basically means your SMTP service is returning not successful. If you're sure your service is up and you can telnet into it then your solution will probably be solved by looking at the smtp server settings, not your code. In my case I was getting this error when I was trying to attach a file. Turns out the default limit for message size is only 2MB. When I increased this limit in IIS's SMTP setup everything started working just fine." No files are getting attached and the site has worked seamlessly until yesterday...so the file size wouldn't be my issue. Thank you in advance! Jeff Hooper