[Решено] Cannot connect other site in WPML

Background of the issue:
I am trying to log into nashtechglobal.com with the active Automatic Translation account and paste the key in Translation Management > Automatic Translation > Settings > Connected Sites in the settings. URL: скрытая ссылка

Symptoms:
I expected to see the migration code add successfully. Instead, I got a 'Migrate website service error' and 'Migration code was not found'.

Questions:
Why am I getting a 'Migrate website service error'?
Why was the migration code not found?