We have determined that this issue has already been resolved because there was no failure reported on the morning of February 17. (Added on February 17, 2019)
A failure where web pages on the Lecture WWW Server could not be accessed occurred during the following period.
Sunday, February 10 at 7am ～ Tuesday, February 12 at 9am
It seems that some users were able to display web pages during the above period, as the failure occurred only on some of the servers.
However, many users may have been unable to display those web pages.
The WWW server process was restarted at 9 am on February 12 and have changed settings to reduce the frequency of similar trouble occurring.
We apologize to users for any inconvenience this may have caused you.