Find your newly added application in the integration menu and open it again by clicking on the listed application.
The opened screen will look similar to the creating screen, with one additional button, namely the ‘Test Connection’
When the fields are correctly filled in it will give you an acknowledgement green check.
If it returns an error it can be that your server doesn't handle the authorization correctly for this you can find the below dropdown in the application.
You can switch between Authorization header and Query Parameters.
Potential solution in case of a redirect error:
Adjust the website permalinks as follows: Go to settings > permalinks and choose 'post name'.