You don't authorize from there. You can remove HE from being authorized, but authorization and re-authorization is done from the HE app.
It seems that at this moment, the Ecobee cloud is having issues. I don't have the integration installed on my hub, and when I tried to add it just now, Ecobee login api responds "We're sorry but we were unable to complete your request. Please try again."
It all worked before. You'll have to wait for Ecobee to resolve their cloud issue before you can connect. My authorization for Hubitat is showing up on their site, but it will not connect. So I probably need to refresh the session. But I cannot to their API to do that, but since I could before and others still have a connection, it must be a cloud issue.