We successfully installed Adobe Acrobat DC on our users machines with a serialized license, however they are not allowed to use all of the features such as 'send for signature'.

We have deployed Adobe DC by creating a package installer using Adobe CC package installer. When we created the file, we selected only Adobe DC, and used a serialize license with our Adobe CC license number.

The program installs successfully and does not require a user to sign in. But, when our users create a document and try to use 'send for signature', they are first asked to sign in. So, they sign in using their own personal adobe ID, because we use Serialize Licensing in our environment. Then after they sign in, they are asked to 'upgrade' their account and pay for an Acrobat Pro DC subscription. But, we already deployed a licensed copy on their machine. 

Please advise on what might be the issue and how we can resolve this.