Cannot connect to app - on device that previously worked

Hello, 1st time poster - have been using the line us for a while with no issues. However I have not used it for a while and on trying to connect my ipad (and android phone) to the robot the app will not find the device. I am connected to the line us setup wifi and can see the config page at 192.168.4.1 with no problem. Its the app that cannot see the device I have tried a factory reset and different power supplys as well as installing the app on a fresh device (andriod phone) with no luck?

any ideas?