Cannot add a new user

​One of our users received the following error while trying to send an agreement in Salesforce.

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​ Please correct the below mentioned error(s). ·        

​ This agreement cannot be sent because the sender is not in the Adobe EchoSign account for this Salesforce organization. Please check with your administrator. ​

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​I have tried to add the user (Echosign Admin > Account Management Console > Users). We have 9 active users and 10 licences. I received the following error:

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​"You cannot add that email address to your account."

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​​Apparently, I need to contact support so that they can approve the domain. But there's no "email support" link  I can click on in order to raise a ticket. I only have the option of using this forum :/.

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​I appreciate your help.

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Thanks,

​Rashida