Magic Mouse not charging

Hi, my Magic Mouse charged to 21% then did not increase further despite being connected to iMac overnight.

next morning, when trying to fix it, I noticed my cable going into the iMac clicked into place then the battery icon in the bluetooth window showed the little lightning symbol indicating the battery was charging. The magic mouse is now showing 100%. so if you have a problem, check your cable is well pushed in at the Mac and the mouse ends and look for the lightning symbol.