I may have a fix.
The fix is working on my PC and mobile so far, even after restarting both from power off.
Some "http" bookmarks created before the site updated, may not work with the new "https" login properly, and will not keep you logged using some browsers
So to fix it if currently affected:
1. Delete your old kennel bookmark
(this step was required at step 1 to work properly on my mobile for some reason, but i didnt need to do it first on my PC)
2. Go to the kennel
3. Log into the kennel
(tick stay logged in)
4. Create a new bookmark to the kennel
5. Use that bookmark from now on