[Bug]: Dataviz charts are not rendered

What is the bug? (in English)

I have a plot defined in the Dataviz tab of Lizmap plugin in QGIS. When I try to render the plot in Lizmap client, nothing is displayed. Upon inspecting my web browsers developer tools this warning is raised:

The data is coming from a PostgreSQL materialized view (the Postgres instance is installed in the same server Lizmap client is). The other layers used by the project are regular Postgres tables and render as expected. In addition, I have the exact same project in another server, also using materialized views, and the plots render as supposed, so I am very puzzled at the 404 error message.

In QGIS Lizmap client, if I try to render a preview of the plot I get another message I don't understand, but might be relevant:

I assume this is NOT a bug, but just something I am doing wrong, but given I have the same configuration in another postgres/lizmap instance and it works well, maybe there's an issue?

Thank you.

Steps to reproduce the issue

Load a materialized view from PostgreSQL
Define a plot based on the materialized view

Versions, safeguards, check summary etc

Versions :

Lizmap Web Client : 3.6.4
Lizmap plugin : 4.3.16
QGIS Desktop : 3.34.7
QGIS Server : 3.34.7
Py-QGIS-Server : not used
QGIS Server plugin atlasprint : not found
QGIS Server plugin lizmap_server : 2.9.2
QGIS Server plugin wfsOutputExtension : 1.8.0

List of safeguards :

* Mode : normal * Allow parent folder : no * Prevent other drive : yes * Prevent PG service : yes * Prevent PG Auth DB : yes * Force PG user&pass : yes * Prevent ECW : yes

Check Lizmap plugin

[X] I have done the step just before in the Lizmap QGIS desktop plugin before opening this ticket. Otherwise, my ticket is not considered valid and might get closed.

Operating system

Ubuntu 20.04

Browsers

Chrome

Browsers version

Version 125.0.6422.142

Relevant log output

No response

3liz / lizmap-web-client