Thanks for sharing your report with us, @Takahiko_Iwaya!
May I ask that you please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so we can have a clear understanding of how your devices are communicating.
Did you transfer your Core to a new machine or was this a new Core database that you used on the PC?
Since noticing this behavior have you rebooted your Core machine?
Regards,
Dylan