Can't connect BTT on my Macbook with my iPhone

I've formatted my Macbook Air, and after that BTT doesn't find my iPhone anymore.
Both MacBook and iPhone are connected to the same Wifi, both have the latest version for BTT, but they can't see each other.
What can I do?

In newer versions of BTT you need to first activate BTT Remote in the settings (because it will soon be replaced by a completely new BTT Remote app and setup)

Thank you Andreas. Now my iPhone can finally see the Macbook, but I can't connect when I try.
This is the error I see on my iPhone.

Do you have a firewall active on your Mac?

No, the firewall isn't active on my Macbook. Just checked it