Need help unrooting SM-G925P

I have a galaxy S6 Edge which you could probably tell from the model number and I recently rooted it. After realizing that my phone was very very sluggish after the root, I decided to unroot it. I have the proper stock firmware for my device downloaded on my computer (Lollipop 5.1.1) but when I tried to flash it manually through Odin I received this error:

<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> G925PVPU2BOH1_G925PSPT2BOH1_G925PVPU2BOH1_HOME.tar .md5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/004> Added!!
<ID:0/004> Odin engine v(ID:3.1005)..
<ID:0/004> File analysis..
<ID:0/004> SetupConnection..
<ID:0/004> Initialzation..
<ID:0/004> Get PIT for mapping..
<ID:0/004> Firmware update start..
<ID:0/004> SingleDownload.
<ID:0/004> sboot.bin
<ID:0/004> NAND Write Start!!
<ID:0/004> FAIL!
<ID:0/004>
<ID:0/004> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

I was surprised to find that this flash wasn't successful because I've flashed this firmware on the phone multiple times with ease. After looking around on google for quite some time, I haven't yet found a solution witch is the reason why I am writing this post. I am not sure how to fix this error and would really appreciate some help. Thanks

This is the file I downloaded from SamMobile's website:
sammobile.com/firmwares/database/SM-G925P/

This is a screenshot of the Odin after running the flash:
prntscr.com/8mpeso