Being redirect to 404 when try to access plugins-install page

It’s just weird to me that I freshly install WordPress multiple times & I still get the problem accessing the ‘Add new plugin’ page.

When I click on the ‘Add New’ under Plugins tab, I have to wait for a while to get a result (it could be that being redirect to 404 or it shows me the Plugins pages with all suggested plugins but this case is very rare)

In case I can access the page normally if I click on any tab or plugin then I will get redirect to 404 page again.

I turned on DEBUG mode but it gives me nothing. I’m using WordPress ver 4.9.6 & PHP7

FYI, I have no plugins or custom theme installed.