I had this problem, all i did was change my cell phone settings in wifi to 2.4G, My phone is either 5G or 2.4G so it wont auto switch. I set my phone wifi to 2.4G and it connected in about 15 seconds..
I just used my new RT700 for a pork loin, tried to get WIFI working for a couple hours with no luck.. UNTIL I had a idea and it worked... I went into WIFI settings on my phone and switched my phone settings from 5G to 2.4G and tried to connect again, It took about 15 seconds and worked perfect...