Licence code and validity
Check the licence key in the customer account and in WordPress for typing errors and make sure that the licence is valid.
Activation slots
If all live activations are in use, another website cannot be linked normally. Remove activations that are no longer required in the customer account.
Lite and PRO versions
PRO requires the active Lite version. Update Lite first if the installed PRO version requires a newer minimum Lite version.
Server communication
The website must be able to reach the licence server via HTTPS. Security plugins, firewall rules or hosting restrictions can block outgoing connections.
After correcting the issue
Check the licence status again and then reload the extensions page.