Is Adobe Sign included in Standard license, but not included in Pro? Pro users get access errors.

[Chris-Has-Questions]

I use the Adobe Teams Admin Console to purchase licenses for my compahy. 

Some users in my company only need Standard, and some need Pro. 

All Standard users are able to use the Fill & Sign -> "Get others to sign" feature to request signatures. 

Some Pro users - not all - receive an error when they click "Specify where to sign": "You do not have access to this service. Please contact your IT administrator to gain access." 

What do I need to do to give Pro users access to request signatures? 

[ProDesignTools]

First off, make sure all your software is up-to-date. If still any issue, then there must be something else at play because:

https://helpx.adobe.com/sign/faq.html

"How do I purchase Adobe Sign?

Adobe Sign can be purchased in the following ways:

Adobe Sign core plans:

• Individual - Get signatures and track responses in real-time.
• Small Business - Get signatures and track responses for small businesses.
• Business - Customize and optimize for your business.
• Enterprise - Build e-signatures into your business systems.

Popular Adobe subscription plans:

Adobe Sign powers tools that allow users to request e-signatures from others inside these applications:

• Adobe Acrobat Pro DC
• Adobe Acrobat Standard DC
• Adobe PDF Pack
• Adobe Creative Cloud memberships that include Acrobat DC

Adobe Document Cloud plans:

The following volume purchase plans are available direct from Adobe and combine Acrobat Pro DC, the Adobe Admin Console, and selected Adobe Sign business plans.

• Adobe Document Cloud for business - includes the Adobe Sign business plan
• Adobe Document Cloud for enterprise - includes the Adobe Sign enterprise plan

Contact Adobe Enterprise sales."