Hrm, odd! Oh well, let’s go through some regular debugging and see if it corrects the issue, if not we may need to go a good bit deeper.
When you try to launch the bridge, does any warnings appear in the console/log?
I’m sure you’d already done this but I have to note it:
So first close the engine, then open your Epic Games Launcher, head over to the engine version you want, and ope it’s Installed Plugins. Remove the Quixel bridge from here or update it if it’s showing update:
Then head down to the vault below and reinstall it to the version you use.
And lastly I have a couple of other solutions from other threads I’ve helped with: