Can anyone tell me why when i send the link from lightroom (not classic) to a client that it sometimes asks them to login or sign up ?
I am guessing that it means sign into say google rather than lightroom. Some clients get the link and see the images others it asks to log or sign in, hence thats what makes me wonder if your signing in to google ?
It would be better if you recommend your clients to create a free Adobe account by signing up. This would keep a consistency and they will not be asked to sign in with other services each time you share images with them.
If your Synced Collection is 'Private' then anyone you 'Invite' must have an Adobe account and [Sign -In]
If you 'Make Collection Public' then anyone with your 'Public' Link can open the link and view the photos without an Account or needing to [Sign-In]. But this then does not allow any on-line collaboration with a Client.