Dear Khun Chaiwichit.
I was informed from Rinnai Taiwan that their email transfer the new system recently: (lisomail.rinnai.com.tw) and they have problem and question as below:
1. Could you please kindly ask for the RTL and hope they could ask their IT department to check RTL's Firewall??
2. Our IT dept determine the problem is RTL's firewall to resist our email system.
3. Please kindly help us to transfer our information to RTL and hope they could check the RTL's firewall equipment.