While still in the or Management section, click on Firmware Update or Firmware Upgrade .
You have a "soft brick". Unplug the power cord for 10 seconds, then plug it back in. If the router works, try the update again from a different browser (Chrome often works best; avoid Safari or Edge legacy). D-link Dsl-124 Firmware Update Download --BEST
D-Link designs different firmware files for different physical builds of the same router model. Check the sticker on the bottom of your router. Look for H/W Ver (e.g., T1, U1, or A1). Installing firmware meant for a different hardware version will ruin the device. While still in the or Management section, click