This thread is resolved. Here is a description of the problem and solution.
Problem: I'm trying to register my site but I get an error message saying that the site key is not valid. Solution: When registering the site it is important to use the same address used in the Settings -> General page Relevant Documentation: https://wpml.org/faq/install-wpml/#register
This is the technical support forum for WPML - the multilingual WordPress plugin.
Everyone can read, but only WPML clients can post here. WPML team is replying on the forum 6 days per week, 22 hours per day.