Adobe Users required to sign back into their user accounts

Hi,

Thank you for posting your query here.

Since you mentioned about the Sign-in prompt recieved by multiple users, you may contact Adobe Support Team and ask them to connect with Acrobat Experts so that they can confirm about any changes affecting several users. 

You may contact Support Team by clicking on : https://helpx.adobe.com/contact/support.html for chat or https://helpx.adobe.com/contact/phone.html
-click the chat icon at the bottom right of the page to open a chat session
-the chat icon looks like '3 dots inside a circle' at the lower right
-type AGENT into the chat window to connect directly to a person rather than the AI

Hope this helps. 

Thank you.