Do not use the charger if the cable appears damaged or the brick feels hot! This is a hardware issue.
Make sure the power cable from the wall is firmly plugged into the power brick.
Make sure the LED light is on the power brick (some bricks do not have LED lights and some bricks have LEDs that do not turn on, but the brick still works)
Even though the light is on, unplug the charger from the Chromebook, unplug it from the wall, wait 30 seconds and then reconnect everything again.
If you have a USB-C Charger, try using another USB-C phone charger in your household. Newer Android phones usually have USB-C Charger. Additional Information: USB-C | Wikipedia
If you have more than one Dell 11 Chromebook in your household, try using another charger.
There are two types of chargers that are pictured below:
Standard Charger has a cylinder tip
USB-C Charger has a flat tip
Standard Charger
USB-C Charger
Tip: USB-C chargers for Android Phones will also charge your Chromebook. However, they might not provide enough power to charge and use your Chromebook at the same time.