Hi! I understand you're trying to modify a route on the komoot web page on your Mac running OS X 10.15.7, but when you make changes, komoot exits or closes without saving those changes. Let's see how we can fix this.

First, just to clarify, when you say komoot "exits," do you mean the browser window/tab closes completely, or does komoot just navigate away from the route editing page? Also, which browser are you using to access komoot?

Meanwhile, I can suggest some general steps to help:

1. Restart your browser: Close the browser completely and reopen it. Then log back into komoot and try editing again.

2. Clear browser cache: Sometimes old data can cause issues. On Safari, you can do this via Safari > Preferences > Privacy > Manage Website Data > Remove All. Then retry.

3. Sign out and back into komoot: Sign out from your komoot account on the website and sign in again to refresh your session.

4. Check internet connection: Ensure your Mac has a stable internet connection during route editing, as interruptions might cause lost changes.

5. Try another browser: For example, if you use Safari, try Chrome or Firefox to see if the problem persists.

6. Make sure you're properly saving the route: When you finish editing, look for a "Save" button on the route planner screen and click it explicitly. Sometimes if you start navigation mode accidentally, saving doesn't appear. Stopping any active recording before editing can help 1.

Could you please try these steps and let me know if the issue still occurs when you attempt to save your route modifications? If yes, I can guide you to deeper troubleshooting or alternative methods like exporting/importing the route to preserve your changes.

Looking forward to your reply!