405 error when adding a new namespace

[jeremygabillet]

Describe the bug

When I try to create a new namespace, I get a 405 HTTP error.

Context

• Hardware: Old laptop or computer
• YunoHost version: 11.2.3
• I have access to my server: Through SSH & through the webadmin & direct access via keyboard / screen
• Are you in a special context or did you perform some particular tweaking on your YunoHost instance?: no
• Using, or trying to install package version/branch: master branch

Steps to reproduce

In the frontend, try to add a new namespace. Nothing happens and you get a 405.

Expected behavior

Be able to add a new namespace.

Logs

Http 405 in Firefox : https://pastebin.com/Y3zbmU9Y

For the record, I tried to change the API URL from /api to /api/v1 as it solved a similar issue for some people. But it doesn't seem to be effective here.

Thanks for you help ! :)