I have a 8900 on T-Mobile (220.127.116.110) and have only ever received the 552 error once - with the new Bing mobile app. I have found no way to install it successfully (and I've tried several times with the same unpleasant result). My restore process has been to use BBSAK (DM is hit or miss) and uninstall Bing. For some reason BBSAK won't uninstall the 4 COD's at one time I have to do it one at a time with a reboot after each - at least I don't have to wipe and reinstall all my third party apps ....
Other than that I have never had a 552 - and I install and try a lot of apps.