I have a small office in China. Their web hosting and e-mail is being hosted by an ISP there. The local employees set everything up. Within the past 2 weeks I have been getting bounce back messages whenever I send e-mail to them. The bounce back error message is “553 Invalid Sender”. Incoming e-mail to me and my e-mail server is redirected to an outside service first for spam filtering and then is forwarded to me. The MX record in my DNS information points to the outside service instead of to my SMTP server. I have been told by my Chinese contact that the bounce error messages are caused by a new anti-spam policy / process recently put in place by the Chinese ISP that marks e-mail as spam if the MX record in DNS doesn’t point to where the e-mail originated from. It’s practically impossible to communicate with the ISP directly because their support pages are in Chinese and nobody there speaks English. Is there anything I can do on my end to get around this problem?