Lightroom mobile sync problem with Classic 7.5

Hi All,

Running a slightly older version of Lightroom (7.5 vs 8.1 now available), and having problems with my sync. Need to upgrade my laptop, but it was working earlier this week, so wondering if anyone has any tips.

Main problem: Changes in lightroom mobile on my phone are not appearing in my Lightroom Classic on my laptop.

Possible source of issue:
- 3 days ago tried the Teekesselchen, duplicate checker plug in.

- Backed up catalogue etc, ran the plug in. Due to the results (and limited knowledge of LR) decided to revert to the backup.

- Opened lightroom, sync disabled because of the prior version of the catalogue.

- At this stage I then realised, I didn't need the catalogue backup, went back to the original catalogue and kept using.

- Sync working fine, so synced some collections to mobile, edited in mobile.
- At this point, sync stopped working. No changes on mobile would go back to Lightroom Classic and vice versa.

Things I've tried,

- Restarting apps on desktop and phone, signing out on desktop and phone.

- Using a prior version of lightroom (7.4)
- Remove all synced photos from Lightroom Classic (removing them from All Synced photos collection). They are no longer in Lightroom Classic All Synced photos, but still are in Lightroom mobile.

- Disabled the Teekesselchen plugin.
- Deleting photos from Lightroom Web, seeing if anything changes on Lightroom Classic (nothing does)

My only next idea is to Delete All Sync Data from Lightroom Mobile using the option in Lightroom Preferences > LIghtroom Sync

Any ideas or tips appreciated.

thanks

Lightroom Classic version: 7.5 [ 1186149 ]

License: Creative Cloud

Language setting: en

Operating system: Mac OS 10

Version: 10.11.6 [15G22010]

Application architecture: x64

Logical processor count: 2

Processor speed: 2.5 GHz

Built-in memory: 8,192.0 MB

Real memory available to Lightroom: 8,192.0 MB

Real memory used by Lightroom: 696.3 MB (8.5%)

Virtual memory used by Lightroom: 1,176.4 MB

Memory cache size: 71.5MB

Internal Camera Raw revision: 1001

Maximum thread count used by Camera Raw: 2

Camera Raw SIMD optimization: SSE2

Camera Raw virtual memory: 168MB / 4095MB (4%)

Camera Raw real memory: 168MB / 8192MB (2%)

Displays: 1) 1280x800