Can anyone recommend a simple and reliable method of sending email notifications and possibly log files attachments from a C# program without requiring the installer or the user to configure the program by specifying server details and email addresses etc. (Mainly because they won't know the details, but also because they could change)

The program will normally be run as a service of a Windows Server, but can be run on a client.

I tried connecting to our own mail server and sending a email to myself, but some ISP's are blocking Port 25 on all servers but their own, so that method isn't working reliably.

Tried sending email through gmail but that was less successful as the port they used was blocked by firewalls. Ditto webservices connecting on weird ports.

Trying to use the local smptservice but did not work either.

It would be nice, but not essential if it was not dependant on my own Internet connection/Servers. (Don't mind them being delayed, but prefer them not to get lost).

Are there any webservices on http/https that allow you to do this sort of thing?

TIA