Accesses token provided is invalid or has expired

Hi all, 

For months I have been trying to use the Acobrat Sign option by sending a contract to a client and myself. Each time I get the same error: An error has occured, please try again. Access token provided is invalid or has expired. I am opening the tool from Adobe Acrobat Pro DC from the laptop´s desktop. 

Hope you can help! 

Thanks!