Hi @t-saito,
Are these publicly accessible? If so, please provide sample URLs. Otherwise, all I can suggest is that you open your browser’s dev tools and check for errors under the “Console” and “Network” tabs as well as check the following logs:
/opt/kaltura/log/kaltura_api_v3.log, /opt/kaltura/log/kaltura_prod.log and /opt/kaltura/log/kaltura_apache_errors*log