How to undo linkset pairing restriction

When tried to create a link between objects of two modules, DOORS report dialog box is popping up with message "A linkset pairing restrication prevents the creation of links from module 1 to module 2. No link will be created.

May I please know, how to undo (remove restriction)  this restriction in the link module, link set?

Which link module, which link set? One-to-one or many-to-many?

Thanks

Re: How to undo linkset pairing restriction
MikeMelon - Mon May 12 11:40:23 EDT 2014

I remembered the steps to fix the problems.

Open your source module and Select File > Module Properties...
Select Linksets tab
Ensure to have an entry showing target module and link module.
Check the "mandatory" box