I ran into a similar issue with the DAP-1522 setup as an Access Point. With MAC filtering turned off everything worked fine. If the only change I made was to set "ON and ALLOW computers listed..." none of my devices could get a connection. They would start to connect but would hang on "obtaining IP address" and never connect. The solution was to add the 2 MAC addresses from my router to the filter list. After that it worked fine.
Unlike my previous access point, turning on MAC filtering also applies to any devices connecting by a wired connection. This means that you must also add the wired MAC address of any computers from which you will administer the DAP-1522 over a wired connection. If you don't you will find that after turning on MAC filtering you will no longer be able to open the admin UI. This happened to me and I had to do a manual reset to access the admin UI and start over with configuration.