Can't Fix Join - Not syncing SMS data between smartphone and PC.

i've just installed Join on Android phone and PC Chrome Extension. I wanted it to be able to send/receive texts on PC and sync these with my smartphone. The set up has not completed. I cannot find help in any Help menu and I'm exhausted trying to solve it,my brain completely frassled.

After installing Join extension on Chrome, I opened the little 'Join' icon in the top RH corner of the page. My phone was listed under Devices, but actually listed twice. On the SMS/Phone tab, I saw the message:

"Seems that the SMS service was not enabled for this device or that some files were not synced.

Enabling SMS remotely now, please wait..."

And a little updating wheel indicated that it was trying to run a process. At the same time, repeated brief notifications would flash up on my smartphone showing that 'Join' was trying to extract information, I think trying to to send SMS message and contact data to the Google server?

Anyway it all seemed to be stuck in a loop for ages. The Chrome extension process continues, after nearly 3 hours. In my smartphone's 'Join' app, I opened up the Logs page, and amongst all the other messages were repeated entries saying: "Couldn't export SMS and MMS". But I did set 'Join' to send SMS data and got a message back saying: "Exporting SMS + contact data to Google Drive". Then: "Success: SMS + MMS exported...". but the Google Extension continues to show this updating wheel with the same message:

"Seems that the SMS service was not enabled for this device..." etc.

I've spent 3 hours on this, on thinking it's all too difficult and not worth the time. Is there anyone who has the knowledge to help solve this? I need the synced SMS function. If I cannot solve it today, I am going to have to uninstall and get a different app. Grateful for a help from a expert. Thanks