Bookmark not adding in version 50 on windows 10?

Please solve my problem

Is there a reason you are using an old Firefox version? I am still using v54. I refuse to lose my add-ons.

Let's start with;

[v57+] Places Maintenance is built into Firefox.

Type about:support<enter> in the address bar.

You will find Places Database near the bottom. Press the Verify Integrity button.

When done, copy and post the results here.