Hi there! I understand you're having trouble logging into the Cogeco Wi-Fi app on your Mac running OS X 10.15.7. Could you tell me more about what happens when you try to log in? For example, do you see any error messages, or does the app just not respond?

In the meantime, here are some initial steps we can try together:

1. Make sure your Mac is connected to the internet, either via Wi-Fi or Ethernet.

2. Check if you’re using the latest version of the Cogeco Wi-Fi app for Mac. If not, updating the app might help.

3. Sometimes, logging out completely and then restarting the app can reset any temporary glitches.

4. Clear any cache or saved login information in the app if that option exists.

Since some users have encountered an error 404 during login, it might be helpful to reinstall the app entirely. To do this, delete the Cogeco Wi-Fi app from your Applications folder and then download and install it again from the official Cogeco support page or App Store.

Let me know if you've tried any of these steps already or if you encounter a specific error. That way, I can guide you through a more precise fix!