Sorry for the second reply but my first one his pending *shrugs*
What are you adding to the hosts file? The ip for the play servers? Generally you should never have to do that, and doing anything by ip these days can strand you because the domain address can resolve to any number of ip's and some will go in and out of service etc, that's one of the main perks of the domain system. If you were able to do that and have it work at least for a while, it sort of sounds like you are having trouble with your dns resolution. When you set up your wifi or the network settings for your carrier, are you changing the name server entries?
I know you don't want to hear it, but it kinda sounds like you are doing something that is causing it.