Smartthings integration no connection

I can’t connect the smartthings integration. I’m looking for help how I can find and check the problem.
This is how far I am just now.

  • I installed HA on a RPI4, configured and enabled duckDNS (its public accessible via https xx.dusckdns.rg)

  • installed the smartthings integration

  • created a personal token in smartthings, configured it and got a popup “installed succesfully” in HA

  • in integrations is no ST integration visible

  • in smartthings at my apps there is nog HA app visible.

Where and how do I start to search for and solve this problem.
Any links or help would be appreciated. I’m new with HA

Regards Ronald

Do you have a valid SSL certificate?

I didn’t install or configure the ssl additionally but the site and cert. info displays:
“verified by Let’s encrypt” Is that ok?

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