Google temporarily disables Gmail accounts if there's been a lack of activity within your inbox. Sometimes it'll mention that the email was disabled due to suspicious activity on your email account.
This can happen occasionally if Interseller is running, but you're not interacting with your Google account as often as you used to (i.e. actively using your Gmail account to send or receive emails within the Gmail app). You can log into the account to reactivate it and you should be good to go. It's a similar concept to websites that have reCAPTCHA to confirm that you're a human and not a bot. This is Google's way of doing that to ensure that your account isn't a bot and that your email account wasn't hacked.