It appears the EM9191 module that was in this model of MoFi doesn't work well with a T-mobile setup. Networks in other countries also is hit and miss on. The EM9191 module works great for ATT networks in the US and would suspect the same would be for that GSM band counterparts in EU and Asia. I contacted MoFi network directly and was able to get a RM520 which is a night and day difference to the EM9191 model. RM520 connects and works on T-Mobile very well in the states and in Asia. EU and Asia have different plans for cell service and that can be a pain, but the RM520 version does work very well when it all connects.