Lost all smartthings devices

Today I upgraded to 104.1 from 103.4, I got the following error whereby for example, developer tools wouldn’t load.
ERROR (MainThread) [hassio.homeassistant] Error on call http://172.30.32.1:8123/api/: Cannot connect to host 172.30.32.1:8123 ssl:None [Connection refused]
Looking at the likely causes and several others having suffered the same dilemma without obvious resolution and I was unable to solve it, I decided to use a snapshot to go back to the previous 103.4 version. When this reloaded successfully I found all my Smartthings devices had become unavailable.
I then successfully updated to 104.1 but they are still unavailable.
Could someone tell me if there’s a way I can get them back on line?
Thanks

Reboot twice
If you have no luck
Remove it and add it again
U will need the token
If you didnt save it you will need a new one

Thanks do I need to delete all entities if I go the latter route?

No the will be removed automatically and reappear once you adf it again

Thanks i’ve tried that, have removed the app.
When I try to add back the integration and put in the original token (which I had) I responds “The token has already been setup.”
Should I therefore delete the integration -just hit delete button on the integration page?
Or
Remove the Webhook which says “This webhook is managed by an integration and cannot be disabled”
Appreciate any advice.

If others have same problem, remove the integration as well as the smartapp and it all comes back as before populated as identical entities.