Adobe Sign emails delivering to spam folder

ALL of the documents that we are sending now are being marked as junk mail OR spam no matter the recipient's email provider: @8395988, @10215394, @AOL, @yahoo, etc. We use this platform to send Power of Attorney documents to new clients and it presents an unprofessional appearance if we have to tell them to check their junk mail folder to find the form from us.

We also should not have to email them in advance to tell them to add this email to their safe sender list so that they will receive it...although we've tried that as well and it is still routing messages to junk/spam folders. We have changed the sender name (under My Profile), but the email echosign@echosign.com that is the sending email appears to be the issue. 

You are providing a service (at a fee) to send documents to people for signature and your email server has been flagged as having a high spam rating. It is your responsibility to clear your spam score so that the service you are providing actually works. We need your help urgently to get this resolved as we have lost several clients due to this.

Thank you

Luke