cannot load fonts

[Luca Ferrari]

Hi all,
I've compiled Emacs 28.1 without any particular option on Ubuntu
20.04. Then I've placed the following in my startup file:

(set-frame-font "Source Code Pro")
(set-face-attribute 'default nil :font "Source Code Pro" :height 140)
(set-face-font 'default "Source Code Pro")


However, when Emacs starts, it prints me a warning message and the
font is not loaded:

Warning (initialization): An error occurred while loading
‘/home/luca/.emacs.d/init.el’:
error: Font not available, #<font-spec nil nil Source Code Pro nil nil
nil nil nil nil nil nil nil ((:name . Source Code Pro) (:user-spec .
Source Code Pro))>

but the fonts are there:

% fc-list | grep SourceCodePro
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-Regular.otf: Source
Code Pro:style=Regular
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-Light.otf: Source
Code Pro,Source Code Pro Light:style=Light,Regular
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-It.otf: Source Code
Pro:style=Italic
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-ExtraLightIt.otf:
Source Code Pro,Source Code Pro ExtraLight:style=ExtraLight
Italic,Italic
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-Medium.otf: Source
Code Pro,Source Code Pro Medium:style=Medium,Regular
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-ExtraLight.otf:
Source Code Pro,Source Code Pro ExtraLight:style=ExtraLight,Regular
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-SemiboldIt.otf:
Source Code Pro,Source Code Pro Semibold:style=Semibold Italic,Italic
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-MediumIt.otf:
Source Code Pro,Source Code Pro Medium:style=Medium Italic,Italic
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-LightIt.otf: Source
Code Pro,Source Code Pro Light:style=Light Italic,Italic
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-BlackIt.otf: Source
Code Pro,Source Code Pro Black:style=Black Italic,Italic
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-Bold.otf: Source
Code Pro:style=Bold
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-BoldIt.otf: Source
Code Pro:style=Bold Italic
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-Semibold.otf:
Source Code Pro,Source Code Pro Semibold:style=Semibold,Regular
/usr/share/fonts/adobe-sourcecodepro/SourceCodePro-Black.otf: Source
Code Pro,Source Code Pro Black:style=Black,Regular


What am I missing here?

Thanks,
Luca