I'm new to Blender and currently working in the 2D Animation workspace. It's likely that I accidentally hit a hotkey that would restrict me from doing so, but for whatever reason, I am unable to grab and move keyframes in the Dope Sheet on a particular save file.
When I start a new Blender project, it works just fine, but I've already made too much progress in this file to start over. I am able to duplicate keyframes and slide them around the timeline, so I've been working around it by doing that and deleting the keyframes in their previous position. As you can imagine, it's not very efficient.