You have received the invite to the discord channel but you are locked out and keep getting the message "email does not exist" or "invalid email." Here are some fixes:
Periods in Your Email Address
Most users don’t know that Discord does not recognize special characters. This also includes periods in your Email address. What you can do is to simply not write the periods that are used in your Email address.
However, if you don’t have any period or special characters in your Email address, one other thing to note is case sensitivity. Although Discord is not known to be case sensitive, you should still try typing the whole Email address in full lowercase. If that does not work, try typing the first letter in capital words.
Discord also seems to give this error whenever you type in the wrong password. Instead of saying “Incorrect/Invalid password”, it says “Email does not exist”. Hence, we suggest you double-check the password that you are typing when logging into Discord. Make sure your keys aren’t capped.
The final reason why Discord gives you this error might be due to the fact that you or someone else has changed the Email in your account. If that is true, then nothing much can be done on your side.
Try contacting Discord’s support team and ask them for help. Cooperate with the team whenever they ask about something. They should help you get through this issue.
If all the above doesn't work!
At the end of the day, you might just have to reach out to them directly to see what's happening. You can do so here: https://support.discord.com/hc/en-us