Hi there! Sorry to hear you’re having trouble logging into Houzz Pro on your Mac. Let’s see if we can get this sorted out together.

First, can you tell me if you’re seeing any error messages when you try to log in? Also, have you tried resetting your password or checked if your username/email and password combination are correct?

Here’s a step-by-step approach to fix common login issues on your macOS 10.15.7 device:

1. Check Credentials: Make sure you’re entering the correct email/username and password for your Houzz Pro account. Sometimes a small typo can cause login failures.

2. Password Reset: If you think you might have forgotten your password, try resetting it using the "Forgot Password" link on the login screen. This will send a reset email to your account.

3. Clear Browser Cache: On your Mac, if you’re accessing Houzz Pro via a browser, clearing your browser’s cache and cookies can help resolve issues related to stored data conflicts.

4. Try a Different Browser: Sometimes the issue could be browser-specific. If you're using Safari, try logging in using Chrome or Firefox to see if that helps.

5. Ensure Internet Connection: Confirm your Mac is connected to the internet without any restrictions. Sometimes firewall or network settings can interfere.

6. Update Browser: Make sure your browser is up to date, as older versions might have compatibility issues.

If you’re using the Houzz Pro app rather than a browser on your Mac, please let me know. We can try uninstalling and reinstalling the app to clear any corrupted files. On macOS, app cache issues can sometimes cause login problems.

If after these steps you still can’t log in, please share any error messages you get or any recent changes you made to your account or device. That way, I can guide you further.

You can also check this official Houzz Pro help article for sign-in issues for more tips: I am Unable to Sign In. What Should I Do? - Houzz Pro

Let me know how it goes! Are you satisfied with this initial guidance?