Engine DJ has recognized a potential issue with connecting an Engine OS device (PRIME series and Mixstream Pro) to WIFI hot spots generated by an iOS device (iPhone or iPad). 

This is a known iOS issue that Apple has acknowledged. For anyone unable to connect their device to an Apple hot spot, Apple has shared troubleshooting and workaround instructions available on their support site. 

Please follow the link below and refer to the "If you can't connect to Personal Hotspot with Wi-Fi" section for troubleshooting and workaround:

If Personal Hotspot is not working on your iPhone or iPad (Wi-Fi + Cellular)