email function doesn’t work #2

Thank you for checking the email delivery status for Akiko Okamoto on the problem of “email function.”We have found that the successful delivery occurred only when the user sent a test email using a mobile network (4G / 5G / LTE) instead of their contracted ISP(Internet Service Provider)'s Wi-Fi. It appears that the delivery succeeded when the user sent the test email using a smartphone while away from home.Based on this, we suspect that the issue occurs when users send emails to members through FTH while connected to fixed-line internet provided by an ISP. It seems possible that the FTH server is blocking or rejecting email transmissions originating from certain ISPs.For your reference, the email addresses and ISPs of the users currently experiencing this issue are as follows:#1ISP: BIGLOBE Inc. Webmail service:Mail address: aokamoto0117@gmail.com #2ISP: NTT MEDIASUPPLY CORPORATION)Webmail service, Mail address: mytsunemi@gmail.comCould you please advise if there is a solution or workaround for this issue? Thank you for your assistance.