Language issue.

Hello, I have two PCs with windows 7 on my network to work with Octoprint, on one of two, octopi is good in English, on the other it is in German. (both with firefox in English).
On my android phone it is in English.

Does anyone have an idea of why I have it in German?

Thank you.

Check your browser's content language settings:

https://support.mozilla.org/en-US/kb/settings-for-web-content-pop-ups-fonts-languages#w_languages