Can’t get itc-306a WiFi to connect

Its-306a will not connect. The guy that was once cleaning my tank, set up the device on his phone a few years ago. Now I have learned how to maintain the aquarium. But I can’t register this device

Please download the latest version of INKBIRD APP.
Please press and hold the ‘up’ button of ITC-306A for 3 seconds to make the WIFI indicator light flash.
Please refer to this post, please make sure the router and mobile phone settings are correct, please use slow flash mode to connect, will it work?