I am not able to add something new in Database (Post, Pages, User, Menu)

Hello WordPress Experts,
I hope you are healthy and happy,

I am getting an issue with my WordPress site – getindevice.com
Let me describe the issue in detail

I am not able to add a post or page, even it doesn’t allow me to add new user or add new comment, I can’t add something new in menu.

What I can do
I can update existing post and pages, I can update menu category, I can add new plugins.

I tried disabling all the plugin and tried with the default wordpress theme.

still the database issue is there.

It is very important for me to fix the issue
Please help me

I am adding screenshots also

https://snipboard.io/PcNeMa.jpg
https://snipboard.io/09Dxc6.jpg

Thanks

The page I need help with: [log in to see the link]