Problems with MySQL ODBC Connection from one machine only...???

I've got a client that I setup a solution utilizing ESS for. Everything was working just fine for a few months. Now when he tries to open up his FileMaker it stalls for a couple minutes and he gets a message that the MySQL connection failed.

I jumped on their server and I can see that in the ODBC Admin panel the connection is no longer working. I've double checked the un/pw which is still accurate but when I try and view the database or test the connection it stalls the same way and eventually tells me it can't connect.

I jumped on the web server to double check the Remote MySQL settings to ensure that his FileMaker machine's IP address was still showing up there and it is. I went ahead and added my own IP address here for testing purposes. I am able to connect to his MySQL databse without any problems using both the MySQL ODBC Connector and using Navicat, a MySQL database editor.

With that I told him there must be something blocking his outgoing traffic on port 3306 (the mysql port) but I've checked his firewall/router and that doesn't seem to be the case. He's also called his ISP to see if they're doing anything funny with that port and they're not.

I know this isn't as much a FileMaker problem as it is a MySQL and ODBC connection issue but I'm hoping maybe somebody in here has dealt with this before and give me a quick tip..??

Any information would be greatly appreciated. Thanks!