Hi @Anonymous,
Could you please share a bit more about the error message within your app?
I have made a test on my side and don't have the issue that you mentioned.
More details about deleting a connection from PowerApps environment, please check the following article:
Deleting connection
Please take a try to clear cache of your browser, and then try it again within the Connections list of your PowerApps portal, check if the issue is solved.
In addition, if the issue still exists, please consider take a try to remove all Apps and Flows which used/referenced this connection from your PowerApps environment and Flow environment.
Best regards,
Kris
