Error: Cookies are blocked or not supported by your browser…

Hey there, I do have a problem with WordPress since I installed it about a month ago. I don’t know a lot about technical stuff and tried everything I could and came across. I cleared my browser history, I cleared all the cookies from my browser, I deactivated the Plugins I have so far.

The Problem: Every time I log in into my Dashboard, the first attempt fails, and this Error comes up: “ERROR: Cookies are blocked or not supported by your browser You must enable cookies to use WordPress”

I am using Mozilla Firefox, by the way, though I don’t know how relevant that is.

I would REALLY appreciate it if anyone here could help me out. Thank you in advance.