It's a conflict between in_mp4 & in_mp3 with how the "aac" extension is detected which was missed when adding local aac file playback to in_mp4 (as part of the work to remove / replace the still re-used in_mp3 from the 5.666 installer) & it's incorrectly being attempted to be used to play streams with the .aac extension in their url.
With build 19994 until a fixed build is available (was reported at the weekend & already fixed internally), you can go to Preferences -> Plug-ins -> Input -> find the in_mp4 entry & open its config dialog & remove the ";AAC" part from the extension list, close the dialog & the stream should play it.
-dro