Hi there! I understand you're having trouble logging into the IHOP app on your Mac running OS X 10.15.7. Let's get this sorted out together.

First, can you tell me if you see any specific error message when you try to log in? Also, have you recently changed your password or made any updates to your account?

While you check on that, here's a simple step-by-step approach we can try:

1. Check Your Internet Connection: Make sure your Mac is connected to a stable internet network. Sometimes, login issues occur due to poor connectivity.

2. Update the IHOP App: Since you're on a Mac, are you using the IHOP app via the Mac App Store or accessing it through a browser? The IHOP app is primarily designed for mobile devices, but if you're using a browser, ensure the browser is updated to the latest version.

3. Clear Browser Cache (if using browser): Sometimes cached data can cause login problems. On Safari, you can do this by going to Safari > Preferences > Privacy > Manage Website Data > Remove All.

4. Reset Password Link: If you've changed your password recently or are unsure, try resetting your password via the "Forgot Password" option in the app or website.

5. Check for Account Lock: After too many failed attempts, accounts may be temporarily locked. Trying again after some time or contacting support might be necessary.

6. Reinstall the App (if applicable): If you use the IHOP app on a compatible device like your iPhone or iPad, uninstall and reinstall the app to ensure you have the latest version.

If you've tried these or have more details on the error message, please let me know, and we can dive deeper. Sometimes there are wider system issues affecting users nationwide, but usually individual fixes sort things out1 6.

Are you satisfied with this initial guidance, or should we try some advanced troubleshooting?