Adobe Sign not sending for one specific email address

There is one specific email address Adobe Sign is no longer working with. This is odd because I have been sending to this email for months without issue. The spelling is not incorrect - Adobe Sign autofills it becuase I have used it so many times before. After I attach the file and click "next" on the Send page, I will sometimes get a pop-up saying a micellaneous error occured. Sometimes it allows me to procede to placing the signautres sites on the documents. The recipient's name is changed to "null" on this screen. Then when I click "Send" it says the document has been sent successfully. However, when I navagate to the "Manage" page, the agreement is no where to be seen. The recipients never recieve the documents either. Please help.