mailing error

Our club uses the FTH mailing system since this September.
We could not send mails when we write the subject with Japanese characters since September 23rd evening,
Strangely enough, we could send mails even if we use Japanese characters on the subject from September 1st to 23rd afternoon.
On that day, Deputy Vppr changed the system so that we could see the name of sender. Does that have anything to do with this trouble?
If there is a solution, please let me know.

You need to use UTF-8 character encoding. Characters that use other encoding that are in the subject have been known to occasionally cause the third party DKIM email security checker script we use to crash. I do not have a workaround for it at the current time, other than to tell you to make sure you use UTF-8 character encoding, and experiment a bit with what works. Any officer can just send an email to their own officer email address as a way to check what works.

Additionally, if you have an example of one of these emails (in raw form showing headers and all parts) that failed, I would like to see it, as this is something I have been trying for some time to find a resolution for.