GalaxyS25 Ultra, DeX not working, blank screen on cable and connection cancelled at wireless display

[Members_aQag0St]

Hi

I upgraded my S22 Ultra with S25 Ultra and my new device DeX is simply not working. While I connect with wire I got blank display and Monitor says going to sleep. And with wireless connection on TV, I get message on TV "connection cancelled".

Does anyone else is also having same issue?

[Day_Walker]

Whats the make and model of your monitor?!

How many USB-C ports does it support?

Which of the USB-C ports are specifically supporting DisplayPort 1.2/1.4 on the connection?!!!

Goto the menu of your display & check:
Autoconnect on USB-C
USB-C 3.0 over 2.0!
MST is auto if listed
Power to USB-C enabled
Auto sleep disabled when USB-C connected. Go through all menu settings for connection.
Try without anything else other than power is connect and your S25U.

Emsure Dex settings are set correctly on your S25 and Dex is enabled.

Take your time.
Think methodically and ignore what your S22 did.
Pretend youre showing your grandmother how it works step by step but remember you cannot get frsutrated at her or angry or huff and puff cause youll break her heart and mom and dad will give ya reminder not to ;) lol.

Trust me it helps thinking that when deducing issues. Deep breath then step by step.

[Members_aQag0St]

My current Monitor is HP E24d G4. It  has 2 Type-c ports one input and another output port. following are the port config

USB-C Video

Auto Switch Input   On

Display Port Mode DisplayPort 1.2

Display Port MST  Auto

USB-C Configuration    USB-C Video +USB 3.0

Other Config:

Autoconnect on USB-C
USB-C 3.0 over 2.0!
MST is auto

[Day_Walker]

Excellent. I have a similar LCD at work. Your settings seem correct. Most likely the port connect to is wrong.

Ensure you're using the upstream port! Diagram attached. Or switch the USB-C cable your using

[Day_Walker]

Oh yeah and wnsure your S25U is connected to the correct USB-C port on the monitor else nothing will work ;)

Cherrs

[Helenna]

Hi Members_aQag0St,

Absolutely! On the HP E24d G4, make sure to connect your S25 Ultra to the USB-C input port, not the output port. The output port is meant for daisy-chaining displays and won't work with Samsung DeX.

Double-check the port labels on the monitor:

• The USB-C input is usually labeled with a laptop or display icon.
• The USB-C output is labeled with an arrow pointing outwards or a chain link icon.

Connecting to the right port is crucial otherwise, nothing will show up. 

Thank you for your suggestions Day_Walker.