Tripp-Lite U442-DOCK8-BINT Manual Del Propietário página 11

Installation
G. If your monitor has a fixed resolution of 4K @ 30 Hz, your
second monitor will automatically downgrade to 800 x 600
or may not even work at all.
H. To fix this, go to General Settings and adjust the extended
monitor resolution to 1920 x 1080 and the refresh rate to
60 Hz. Click Apply to save settings.
Resolution (NB)
1080p @ 60 Hz
Resolution (Monitor)
4K @ 30 Hz
4K @ 30 Hz
1080p @ 60 Hz 1080p @ 60 Hz
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X
800 x 600