The ten year old U2713HM was only tested/validated in Windows Vista/7/8/8.1. The last tested/validated DDM for this ten year old U2713HM was version 1.56.2110. Uninstall DDM 2.1.1.36Restart the XPS 15 9560Install DDM 1.56.2110Restart the XPS 15 9560 and then test DDM 1.56.2110
I have installed DDM 2.1.1.36 on my XPS 15 9560 laptop but it asks me to connect a supported Dell monitor.  My laptop is connected to a single U2713HM monitor via: OSD shows DDC/CI is enabled.  Even if I disconnect the monitor, the same message pops up when I try to open DDM on my laptop's display.  SupportAssist 3.14.0.91 says my system is up to date on drivers and downloads, and the scan hardware test does not show any issues.  Windows Update says my system is up to date.  Windows 10 Pro 64-bit, Version 22H2, OS build 19045.3324, Windows Feature Experience Pack 1000.19041.1000.0  I would appreciate your help.
U2713HM, Windows 10, DDM, please connect a supported Dell monitor