I know I've found an answer already on here a long time ago but for whatever reason, I can't log into my launcher or the website. I know my information is correct, and my account hasn't been hacked. (At least I hope it wasn't) The launcher error is 'Invalid Email or Password' I know it had to do with a certain file but I just can't remember what file it was. If anyone can help me or find the post please do as it will really lower some of my stress levels. :)
If you can't log into the website either, it's unlikely a local file could affect that.
Mojang is known (1, 2) to block login attempts/throttle them after several failed logins. It's possible you failed your login a few times (due to something like a typo) and are being IP blocked since then. Double check your entered credentials (including things like caps lock and/or num lock) and try again in about 30 minutes.
You can always reset your password if needed be.
If you're concerned whether your account has been hacked, you should check your email address on Have I Been Pwned. It's a reputable website that scans data breaches and logs emails found in them. If you email turns out to be in a data breach, consider changing your passwords.