Hi Mr. Saito,
I am pleased that the server is working for you now.
OPeNDAP is the company that develops and provides (for free) the Hyrax server software that you encountered. There are a great many instances running at different institutions around the world. This means that without the complete URL of the server that you interacted with I have no possible way to know which instance of the server with which you were working.
With the complete URL we can easily determine the version of the Hyrax software that is running at that location, and often determine which institution is hosting there server. With that information we can reach out the to appropriate person to see if they can action to correct a problem that they may not be aware of. For example, the Hyrax server can at times encounter issues like resource starvation (a lack of available memory or disk resource) that can be addressed by human intervention.
Sincerely,
Nathan