Exactly you stated you changed location several times. When that happens you get flagged and softban. stop using the account for a couple of hours and try again at a nearby location. If you location hop that much you're gonna get softbanned
I'm not jumping crazy far distances, once I get the error I stop the bot and wait a few minute and go to the next closes pokestop then start back up. I still get the error even after starting it up for the first time with a 12 hour break. But I'm glad they have superior mods here who know all!
Started up the bot again, this time it clearly shows I'm not softban. But its double looting the pokstops, loots its once gets the items then trying to loot again.