Sage 50 is a software program and easy to use that anyone can use this. Mostly the Sage error 1721 arises in your system during installing. This error indicates certain problems with the Windows installer package. If you have already followed all given solutions in the Documents but still you are facing this Sage 50 Error Code 1721. If the user wants any help with Sage products, they can directly call us on our toll free number +1-800-942-6705. Sage 50 technical support number. We are always here by 24*7.