LG Ultrafine 5k doesn't turn on with Mac pro cylinder!

[deepredbear]

Hey there guys!
I have just received the lg monitor + the adaptor for mac pro that I purchased online from belgium (I live in Casablanca). I have a mac pro 6 core intel xeon 5 and I am a sound engineer upgrading my system (using pro tools HD).
First day, everything went brilliant, I used the monitor via the thunderbolt 3 adapter (usb c) connecting the LG thunderbolt port 3 to my thunderbolt 2 port on my mac pro. I installed pro tools hd, upgraded everything and it was spot on! The next day, I turned on my mac pro (everything was plugged as usual) But the LG Ultrafine monitor's screen went black! not turned on at all! I tried unplugging and plugging the thunderbolt cable and the adapter, nothing works!? it's like it's not even detected! I tried hooking up an old ASUS monitor I had, through the hdmi port of my mac pro! and it's working of course, then I tried to hook up the lg as well via the adaptor as a second screen, it seems like my mac pro doesn't even recognize it! it's undetected!! I don't know what happened?! I don't know if someone has the same problem!! I just need some help guys! if there is anything I can do... Thanks

 

[bknaepen]

Did you try to reboot with the display connected? (sorry to ask if it sounds too obvious...).

 

[deepredbear]

Did you try to reboot with the display connected? (sorry to ask if it sounds too obvious...).

Hey there/ i did yeah ! thanks for your reply man anyways! i really dont know what happened! first time trying it, works fine, turn off mac pro at night, turn it on the next morning and the LG doesnt wanna turn on! not even detected!