LR classic not syncing to LR mobile app

[intelligent_listener5D55]

Help needed please. My LR classic (windows PC) has stopped syncing to my mobile app devices (Android). Done everything right on the desktop ie. pictures are put into collections inside collection sets and the '2 way arrow ' is switched on.  the sync panel says I have used 3gb of my 20gb allowance.

Other odd thing is when I open  a new catalouge and try to sync it tries to sync all photos in my entire Lightroom environment (and not just the ones in the new catalouge) 

[Rob_Cullen]

"odd thing is when I open a new catalouge and try to sync it tries to sync all photos in my entire Lightroom environment"- That is to be expected.

You can only Sync one Classic catalog with Lightroom (Cloud).  Every time you swap the sync to another LrC catalog it will automatically download all photos in the Cloud library.

See the pitfalls of changing a synced catalog in this post by CalifDan-

NEW LRC CATALOG AND CLOUD SYNC