[AC Question]

Phone Details:
Spring Galaxy S4
Baseband Version L720TVPUBNG5
Used CF autoroot

This all started a few days ago. The latest OTA update came out and my phone kept telling me I had insufficient storage for the update. I figured it was because I had it rooted. I followed QBking77's video for Unroot / Unbrick. Downloaded all files reccomended in the video.

Every time I try to flash with ODIN I get a failure. I have tried three different .tar versions at this point. Two different cables, both came with an SGS4.

I finally had enough and used the factory reset. After factory reset I used KIES for my update. The phone took it fine and rebooted. Although now I have no WIFI.

When initiating WIFI it will tell me that the security application has rejected a request to protect my phone. I deleted lookout security even though I have never used it.

Does this have something to do with KNOX? Is there a way to completely flash my phone back to a stock state with the original recovery and rom?

[Rukbat]

I finally had enough and used the factory reset. After factory reset I used KIES for my update. The phone took it fine and rebooted. Although now I have no WIFI.

That's why an update should fail even if the phone has once been rooted, but now it's not. Something could have been changed when it was rooted, that is causing the problem.

Does this have something to do with KNOX?

Not unless you installed it. What's in the phone are just the hooks to let Knox work if you download and install it.

Is there a way to completely flash my phone back to a stock state with the original recovery and rom?

SamMobile Firmwares, look for your model of S4, then your carrier/country, download the file (you'll have to create a free account), unzip the files in it and load them into Odin. From there you should be stock out-of-the-box.