[Resolvido] Unable to translate the pages and posts after migrated to live site

Background of the issue:
I am trying to do the translation after migrating to the live domain.

Symptoms:
The system is unable to translate pages and posts. I expected to see the translation page, but instead, I got the message: 'WPML didn't manage to translate this page.'

Questions:
Why is the system unable to translate pages and posts after migration?
How can I resolve the issue where WPML doesn't manage to translate the page?