Hi Roman,

The error message you are seeing indicates that there is an issue with the JSON data being returned by Odoo on your Zebra TC21 devices. Here are some steps you can take to troubleshoot and resolve the issue:

1. Check the Odoo server logs to see if there are any errors or warnings that may be related to the issue. Look for any messages that mention JSON or the specific error message you are seeing.

2. Verify that your Zebra TC21 devices have the correct date and time settings. If the date or time on the device is incorrect, it may cause an SSL error.

3. Try clearing the cache and data of the Odoo Android app on your Zebra TC21 devices. This will delete any temporary files or data that may be causing the issue.

4. If none of the above steps resolve the issue, try uninstalling and reinstalling the Odoo Android app on your Zebra TC21 devices. This will give you a fresh install of the app and may resolve any issues with the installation or configuration.

If none of these steps resolve the issue, you may need to contact Odoo support for further assistance or troubleshooting.

Regards