Hopefully this will save someone a few hours of trouble...

We have been using Google Apps and have had no problem using smtp.gmail.com with the store. However, today we noticed the store was not sending out any emails. The users did not get any error messages and the store log did not log any errors or exceptions.

So I went to the admin site Configurations > Email and tried to send a test message and got the following error:

Code:
Unable to read data from the transport connection: net_io_connectionclosed
Doing a quick google search indicated this error is usually thrown when a connection to the smtp server cannot be established. So I did a quick telnet test to see if the server was running as instructed at the very bottom of this google help page.

I could connect to the server just fine.

Then I thought something might be wrong with my account. So I went to try and log into the account via gmail.com and was presented with an updated terms of service which I had to click agree on.

Once I clicked agree everything started working fine again on the storefront. So Google had basically locked out the account until we accepted the new terms of service. Therefore we could not sign into the smtp server. We use an unmonitored account to send out store notifications so we barely log into it.