Last week, had no issue getting in, now it says that I do not exist. Leave things alone if they work!
There have been a lot of back-end problems recently that the admins have been dealing with as fast as they can.
Can you still log in to the regular Scoutbook interface? What positions does it think you have there? If it doesn’t see you as a Den Leader, it won’t permit access to the DLE interface. You can try going to My Dashboard -> My Account -> My Positions, select your DL position, tick the “I agree to join the unit roster” box and click “Update”. That should restore your position if it’s fallen off for some reason. It may require a Unit Admin (Cubmaster, Chartered Org Rep and Committee Chair are all admins by default) to go in from their end and approve your position via My Dashboard -> My Units -> Unit Roster -> click on your name, the DL position, and “Approve”.
If you can’t log in to Scoutbook at all, there may be a problem on the back end with your my.scouting credentials. I had to reset my password yesterday as a result of the back-end problems I mentioned at the beginning. That might fix your access issue.