Unable to flash TWRP [FAILED (remote: Command not allowed)] - Xperia Z5 Compact Q&A, Help & Troubleshooting

Hey all,
--> I'm trying to flash TWRP to my Sony Z5 Compact, but the flash fails during the writing process of the .img file
--> It gives me the following error: FAILED (remote: Command not allowed)
--> I am currently running build number 32.3.A.2.33
--> The phone is NOT rooted (but this should not matter I think... because I cant do that either if I cant write anything to my phone...)
Things that I have already done:
1. I enabled OEM unlocking in the developer options.
2. I enabled USB-Debugging in the developer options
3. The ADB and Fastboot drivers are working correctly
Does anyone know how I can fix this issue? I have already browsed the web for a fix, found a lot of people having the same issue, but nothing has worked for me.
Thanks in advance!
Horizon

---

i didnt see you unlocked the bootloader, i guess this is the problem
Here link:
https://developer.sonymobile.com/unlockbootloader/unlock-yourboot-loader/
its the easy part,
besure you backup everything bootloader for me did factory rest
i did with CMD terminal
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
its always good idea to backup also DRM keys also unlock takes your warranty
A. Install the Android SDK and the device drivers
1. Download and install the Android SDK. The SDK Manager is included in Android Studio, but you don’t need to install more than the basic Android command line tools. These can be found at the bottom of the page.
Tip: Take note of the installation path, you may need to access specific files later.
a. If you are running Windows: You need to install additional drivers.
1. When completing the installation, open the Android SDK Manager and go to the Extras folder to install the Google USB driver.
2. Download and install an updated Fastboot driver. This is the standardandroid_winusb.inf-file, with a few lines of code added to enable Fastboot to support Sony devices.
3. Replace the original android_winusb.inf-file with the downloaded file in theusb_driver folder, located in the Android >sdk > extras > google folder on your computer.
b. If you’re running OSX or Linux, you are not required to install any additional drivers.
2. On your device, turn on USB debugging by going to Settings > Developer options and click to enable USB debugging.
a. If your device is Android Jelly Bean 4.2 or newer: Developer options are hidden by default. To enable, tap on Settings > About Phone > Build Version multiple times. Then, turn on USB debugging by going to Settings > Developer options.
B. Connect to Fastboot
1. Turn off your Xperia™ Z5 Compact.
2. Connect a USB-cable to your computer.
3. On your Xperia™ Z5 Compact, press the Volume up button at the same time as you connect the other end of the USB-cable.
a. Windows users: When asked for a driver, open the Devices and Printers directory, click on the fastboot driver and press Update. Browse and point towards the location of the new android_winbus.inf file.
4. When your device is connected, open a command window on your computer and go to the platform-tools folder within the Android SDK folder.
5. Enter the following command:
fastboot devices
Click to expand...
Click to collapse
6. Verify that you get an answer back without any errors.
C. Enter unlock key
WARNING! The command below contains your unlock key. If you perform this step, you will unlock the boot loader. This may void your warranty and/or any warranty from your operator.
1. If you still want to unlock the boot loader of your device, enter the following command:
fastboot -i 0x0fce oem unlock 0x(here your code you got by sony)
Click to expand...
Click to collapse
2. Verify that you get an answer back without any errors.
D. Done!
You have now unlocked the boot loader of your device
good luck, update if got it right
PS .i posted my imei by mistake hope i didnt miss to remove another :X

---

Hey man! Thanks for the quick response! Went right to work with it this morning... and it fixed it!
--> I completely missed the next steps from Sony. for some reason I thought that OEM unlocking option would do the magic lol..
--> After I unlocked it through cmd it was a breeze from there! Got my TWRP on there and the Lineage ROM
Thanks!