Just an FYI for all..

A PC HDMI out port was never designed to "upconvert" to a monitor DP in port via a straight converter cable. You would need this Active Converter box =

PC HDMI out --> HDMI to HDMI cable --> HDMI in to DP out converter --> DP to DP cable --> Monitor DP in

All, this question has come up so many times that there's a sticky in the FAQ Monitor at the top of this Monitors board =

PC HDMI/DVI/VGA out to Monitor DP/mDP in

DisplayPort to HDMI cables only support connecting a DisplayPort source to an HDMI display input.  They do not support going in the opposite direction as you're attempting.  The reason is that most (but not all) DisplayPort sources support "Dual Mode DisplayPort", which allows a DisplayPort output to fall back to HDMI signaling.  But HDMI outputs have never supported switching to DisplayPort signaling, and displays do not support receiving a native HDMI signal on their DisplayPort input.

Dell seems to be omitting HDMI inputs from their E Series displays, possibly because the E Series is their lowest end offering and HDMI ports and connectors require the vendor to pay a royalty on every HDMI port or connector they install on a product, whereas DisplayPort is royalty-free.

Be sure to specify what system you're trying to use this display with (always a good idea when asking for technical assistance, fyi), but the only way to use that DisplayPort input is from either a DisplayPort or USB-C port on your system, and the latter is only an option if your system's USB-C port supports video output, which not all systems with USB-C ports do.  Otherwise, there are HDMI to VGA adapters/cables, but that of course means using VGA, which won't look as good.  So if you can't use the DisplayPort input and don't want to use the VGA input, I would suggest returning the display and then getting one that actually has an HDMI input.  Be sure to check the Tech Specs to confirm.  That information is always published.