Dash.js does not work with simple server setting

[paperflight]

I have dash.mpd file ready in the root dict of the server. I can use MP4Client or GPAC -gui and IP address to access the video.

However, when I run the server and Dash.js. The server shows that something is trying to set up the connection but failed for some reason.
[03:06:03.747] Runnning ~/node-gpac-dash/gpac-dash.js using /usr/local/bin/node version v12.13.1 in ~/node-gpac-dash [03:06:03.752] Server running on port 8000 on all IP in normal mode [03:06:09.860] Request for file: 'tiled1M_dash.mpd' at UTC 1635386769859 [03:06:10.382] Request for file: 'tiled1M_dash.mpd' at UTC 1635386770381 [03:06:10.894] Request for file: 'tiled1M_dash.mpd' at UTC 1635386770894 [03:06:11.405] Request for file: 'tiled1M_dash.mpd' at UTC 1635386771405 [03:08:24.260] Request for file: 'tiled1M_dash.mpd' at UTC 1635386904260 [03:08:24.775] Request for file: 'tiled1M_dash.mpd' at UTC 1635386904775 [03:08:25.289] Request for file: 'tiled1M_dash.mpd' at UTC 1635386905289 [03:08:25.853] Request for file: 'tiled1M_dash.mpd' at UTC 1635386905852

The Dash.js is returning:
http://localhost:8000/tiled1M_dash.mpd is not available

My system: Ubuntu 21.04

My GPAC:
gpac - GPAC command line filter engine - version 1.1.0-DEV-rev1414-g602d94512-master (c) 2000-2021 Telecom Paris distributed under LGPL v2.1+ - http://gpac.io

My npm: @8.1.1

My Dash.js reference client: 4.1.1

Does anyone have an idea about this? By the way, I try to set the HTTP server with GPAC HTTP command but it does not work eighter. So I think it might be the problem of some settings. My ufw is disabled. I check many possible settings. So I just ask here.