Cannot install theme manually

Hi,

Whenever I try to install a theme manually like this: https://prnt.sc/i2324b… I get this error message that pops up instantly after pressing the ‘Install Now’-button: https://prnt.sc/i232jx.

After the initial installation of WordPress, the values in the Settings > General looked like this: https://prntscr.com/i23btl.

I changed these values to this now: https://prntscr.com/i23b4t (by adding the “www.” value to each text field).

Could this be the issue somewhere in the DB maybe?

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