Try my tool 
for Firefox + MetaMask wallet 
Available on my GitHub:
https://github.com/0xLuigi/sql-metamask-id-viewer
PS: It is simple and safe python tool 
works completely without internet.
Today I also added a simple html version 
But before using it, read the entire readme file.
If you haven’t written down your MetaMask seed phrase and you’re using Firefox, you can try this guide: https://community.metamask.io/t/metamask-blank-screen-on-firefox-but-no-seed/12971/32
Other possible solutions:
Check for conflicting extensions - Temporarily disable other crypto wallets or extensions that might conflict with MetaMask.
Clear cache and cookies - Delete browser data, especially for sites where you use MetaMask, and check if you’re using an updated browser.