I recently, (APRIL 2020) had a Blackvue DR900S-2CH Dash Camera installed in my car.  Everything about this device is quite good except it would fail to reliably connect to the cell phone WiFi.  I quickly found the solution.  I use an Android LGV30 phone.  I went into the cell phone settings and chose Network & Internet portion settings.  All I had to do was to turn Mobile Date Off.  Then the BlackVue cell phone application held a solid connection when I chose the BLACKVUE WI-FI menu selection on my cell phone.  I even drove around a while with my cell phone showing the live front dash camera signal.

Caution:  I did find a possible problem with turning off Mobile Date.  I drove over to Starbucks to buy a drink and I always pay using my cell phone Starbucks application in the phone.  Every time I open the Starbucks cell phone application I must choose “Scan in store”, a small sub menu option.  Pressing that small menu button then presents a new screen that the Starbucks people can scan to take money out of my account.  It would not work.  Was this because I turned off Mobile Data?  Or did I loose Internet?  I was forced to pay cash!  If this happens to you, just turn Mobile Data back on.

Just to check other cell phone menu options out:  I went into the sub menu of Mobile Data, after Network & Internet.  By pressing on that menu selection, “Mobile data”, I found two sub menu items:

• Mobile: You can scroll down and view all the applications using mobile data.  BlackVue is one of them.  There are two on/off buttons you can choose.  I turned on both Background data and Unrestricted data usage.
• Wi-Fi:  You can scroll down and view all the applications using mobile data.  BlackVue is one of them.  There are two on/off buttons you can choose.  I turned on both Background data and Unrestricted data usage.

Other Settings: 

• Special Access > Modify system settings:  BlackVue showed “No”  (I have no opinion for this setting except to say that it was set to “No”.
• Special Access > Wi-Fi Control > BlackVue “Allowed”  Allow app to control Wi-Fi.  It looks like you had better turn this on if not on already.