For troubleshooting purposes, please try the below steps -
Disconnect the synchronization from the connected device and then enable the synchronization again. I would also suggest restarting your NextCloud server .
Could you please check and confirm that the time setting is set to automatic on all the devices and there is no time difference? If they are not, kindly set it to automatic.
Ensure that you have allowed access to Enpass in your Firewall/Antivirus Settings. Moreover, if you are using any VPN service, try disabling it to check if the issue persists.
Create a manual backup of your data and then reinstall the app on the affected device.
If the issue persists, please share the below details with me, and I’ll have this checked for you -.
The version of the Enpass app and OS you are using on all your devices.
Any VPN/Antivirus service you are using.
If possible, could you provide us with a demo account with its URL, username and password on support@enpass.io ? It will help us immensely in investigating this issue on our end.