Describe the issue you are experiencing
A clear and concise description of your issue:
Bookmarks synced from Firefox on desktop Windows 10 PC can no longer be synced to Chrome browser on Chromebook. Syncing has worked flawlessly for months but has just stopped working suddenly.
How can the issue be reproduced?
Steps to reproduce the behavior:

1. Install latest 1.5.1 version of Xbrowsersync on Firefox latest version 72.0.2 (64 bit) on Windows 10 desktop PC. Initiate initial sync on https://xbrowsersync.freerangecloud.com/ service
2. Install latest 1.5.1 version of Xbrowsersync on Chrome browser latest version 79.0.3945.119 (64 bit) on fully up to date Chromebook.
3. Click on 'Already got a Sync ID?'
4. Enter sync ID and encription password. Click on 'Sync'.
5. 'Syncing' message appears and never finishes, even when left for 20 minutes or more.
6. Setting up a new sync and repeating the process results in the same error. Has previously worked fine with no issues.
7. No new extensions have been added or updates to other extensions have been carried out on the affected Chrome browser which may conflict with Xbrowsersync.

Screenshots
If applicable, add screenshots to help explain your problem:

Desktop browser
Please complete the following information for all affected desktop browsers:

• OS: Windows 10
• Browser: Firefox
• Version: 72.0.2 (64 bit)

Laptop browser with error
Please complete the following information for all affected laptop browsers:

• OS: Chrome OS
• Browser: Chrome
• Version: 79.0.3945.119 (64 bit)

Application log
Please include the logs from the affected clients:
Download the Application log from the Settings panel and paste the contents here.

2020-02-11 07:50:34.268 [trace] Installed v1.5.1
2020-02-11 07:50:34.288 [trace] Starting up
2020-02-11 07:50:34.352 [trace] {"displayHelp":true,"displayPermissions":true,"appVersion":"1.5.1","platform":{"name":"chrome","version":"79.0.3945","mobile":false,"os":"Chrome OS x86_64"}}
2020-02-11 07:50:45.676 [trace] Optional permissions granted

End of log