jpm run command has an invalid manifest

I am following this tutorial to create add-ons for firefox.

When I run jpm run -b "C:\Program Files\Firefox Developer Edition\firefox.exe", the console gives me the following warnings:

1546371425561 addons.xpi-utils WARN addMetadata: Add-on @celestus-firefox-extension is invalid: Error: File C:\Users\user\AppData\Local\Temp\3f4ff82f-9dfc-4065-a6c7-7e9719d0c286\extensions@celestus-firefox-extension.xpi does not contain a valid manifest(resource://gre/modules/addons/XPIInstall.jsm:557:11) JS Stack trace:

loadManifest@XPIInstall.jsm:557:11

awaitPromise@XPIProvider.jsm:188:3

syncLoadManifestFromFile@XPIInstall.jsm:620:10

addMetadata@XPIDatabase.jsm:2334:21

processFileChanges@XPIDatabase.jsm:2686:21

checkForChanges@XPIProvider.jsm:2581:34

startup@XPIProvider.jsm:2159:25

callProvider@AddonManager.jsm:203:12

_startProvider@AddonManager.jsm:652:5

startup@AddonManager.jsm:805:9

startup@AddonManager.jsm:2775:5

observe@addonManager.js:66:9

1546371425681 addons.webextension.screenshots@mozilla.org WARN
Loading extension 'screenshots@mozilla.org': Reading manifest: Invalid host permission: resource://pdf.js/

1546371425681 addons.webextension.screenshots@mozilla.org WARN
Loading extension 'screenshots@mozilla.org': Reading manifest: Invalid host permission: about:reader*

Firefox opens as expected, but the icon that is supposed to be there is not there.

I can't find anything that could help me fix that. Some said it was because of a JSONwith an invalid format but everything is clear on my side.

Could anyone help me solve this problem?

edit: Just tried with a console with admin rights, does not change anything.

The solution was just because of a newby mistake. I run firefox dev edition 65.0b7 but this tutorial works for firefox 57 and bellow.

Answer was given here