Are you using any password add-ons/programs?

No. All list of my addons:

• AliPrice Assistant - Price Tracker 7.5.6
• AutocopySelection2Clipboard 2.6.0
• BandcampVolume 1.0.1
• Bloody Vikings! 0.9.4
• Country Flag + 0.1.8
• FoxyProxy Standard 6.3
• Gesturefy 1.2.2
• Group Speed Dial 9.2
• No Coin - Block miners on the web! 0.4.14
• Reload Skip Cache Button 1.2
• Save In… 2.6.2
• Save Page WE 10.0
• Tab Count Icon 0.7.1
• Tab Session Manager 3.1.2
• uBlock Origin 1.16.8
• Violentmonkey 2.9.4
• VkOpt 3.0.5.2
• Zoom Image 2.6

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

And just to make sure; Type about:preferences#security<enter> in the address bar. Look under Logins,

Note: For Firefox 56+ its; about:preferences#privacy Look under Forms & Passwords +++++++++++++++++++++++++++++++ Turn on Remember Logins. To check the passwords you have listed, press Saved Logins.

Can you fill the login form via the right-click context menu?

Is this a secure (HTTPS) or an insecure (HTTP) page?

In safe mode: https://i.imgur.com/wk5Y1ML.png

In normal mode: https://i.imgur.com/5qjTv6q.png

In normal mode form is empty!

cor-el said

Can you fill the login form via the right-click context menu? Is this a secure (HTTPS) or an insecure (HTTP) page?

No, in normal mode I can't do it.

You can try the Firefox version from the official Mozilla server if you currently use a version from the repositories of your Linux distribution.

If the passwords work in Safe Mode,

It could be the work of one of your add-ons, or it could be Hardware Acceleration. How to disable Hardware Acceleration {web link}

Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; <Control> (Mac=<Command>) <Shift> A)

In the Add-ons Manager, on the left, select Extensions. Disable a few add-ons, then Restart Firefox.

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All Of them.

If the problem continues, disable some more (restarting FF). Continue until the problem is gone. After, you know what group is causing the issue. Re-enable the last group ONE AT A TIME (restarting FF) until the problem returns.

Once you think you found the problem, disable that and re-enable all the others, then restart again. Let us know who the suspect is, detective.

I solved my problem by refresh firefox! Thx to all

That was very good work. Well done.