Why does ATLAS.ti (5,6,7,8) not accept my license key?

Why does ATLAS.ti (5,6,7,8) not accept my license key?

I am trying to install ATLAS.ti, but when I enter license key I was sent, I see the error message: “Please enter the correct serial number”.

There are several possible causes for this problem. Please go through the suggestions below in the order in which they are presented.
Note: “serial number” and “license key” are used synonymously!
  1. Make sure you enter the license key exactly as provided. Be particularly careful not to include any unwanted spaces before or after the digits when copying and pasting the key. Try copying the row of digits to a plain text editor (such as Notepad) first and be careful to select ONLY the actual letters and numbers, with no additional spaces, dashes etc.
  2. Check if your order was for TWO licenses and if you were sent TWO license keys accordingly. Do not accidentally enter BOTH license keys as one.

If you have a program version NEWER than ATLAS.ti 8, please see this information: https://atlastihelp.helpscoutdocs.com/article/373-i-have-purchased-an-atlas-ti-license-what-do-i-do-now.