IP address block by Authorize.net

I have had to assign an static ip address to one of my domains that processes orders through Authorize.net because the IP is either being blocked by Authorize.net or they are saying it is my server that is causing the problems. This is the response from their tech support after my shopping cart programmers contacted them about trouble with response relay url at our shopping cart domain and authorize.net blocking the above IP:

This would tend to mean that Your server will not let us in. Is there a firewall on the server that is blocking our response. What you are describing is telling me that the response is being received and is displaying every page except the server in question. This means that there is something about this server that is not working correctly. Make sure that the server is not already over burdened. It might be that the server is unable to respond to us in an adequate timeframe.

I really don’t think my server is overburdened as I don’t have any high traffic sites. Plus as soon as I assigned a static IP that wasn’t the above one things worked.

Does anyone have any experience with this and Authorize.net? I have written to support to see if they can provide any clarity as maybe they are blocking something on that IP from coming in – who knows? I just need to know that DH isn’t doing something from this side, before I go after Authorize.net. :slight_smile: