blue sq. with ? mark mean?

Greetings Kalolab,

Is this happening in Mac Mail, or in Safari?

Troubleshoot email problems in Mail on Mac

If Safari on Mac doesn't open a webpage or isn’t working as expected

"To reload a page, choose View > Reload Page, or press Command-R. If you can't reload, make sure that you're connected to the internet.

If you still can't reload:

1. Press Command-Q to quit Safari. If Safari doesn't quit, press Option-Command-Esc to force Safari to quit.
2. Open Safari again and try to load the page. When Safari opens, if it automatically opens pages that you don't want to open, quit Safari again, then press and hold the Shift key while opening Safari. "

Take care.

Kalolab,

Thanks for using the Apple Support Communities. We’re glad to hear that things are working as expected again.

Thanks for keeping us posted. Cheers!