I used to be able to use beginRefundRequest function on Testflight, but now I can't

I used to be able to use beginRefundRequest function on Testflight, but now I can't.

Maybe last month I can use beginRefundRequest function on Testflight. Today, I can't use it, and there are messege「返金できません(can not connect)」.

Does anyone know about this issue?

This is the image of that error.

Can you file a feedback assistant ticket with a sysdiagnose? feedbackassistant.apple.com

OK, I just make ticket with sysdiagnose. Thank you.

Hi, I did file the feedback : FB11893338, but noone reply to that..

I used to be able to use beginRefundRequest function on Testflight, but now I can't
 
 
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