I have signed in to various businesses and it would connect but would shortly thereafter give me that error, even when I have 5 bars or whatever. Makes no sense.
Yeah that happens with my wifi at work (London underground). First I connect via the normal method...and I get the unstable message...then I launch my web browser and I get the ee splash screen with an add...Once that page has loaded the connection message clears and all is ok. Guess they have it set up so that you don't get full speed until you have looked at the advertisment. I have to redo this every half an hour.