Can't Validate Server

[Billblast]

When I try to validate the server for Sendgrid I receive that attached message.

Please let me know what the problem could be?

Thanks

 

[twisted1919]

This happens if you send too many validation emails and then you click the link in one of hem which is no longer active. Remember that only last validation email is valid. if you send 10 validation emails and you click on the 5th email, you will get this page, you need to click last email.