Everything seems ok but no feeds work

[laspic]

Sorry for the inconvenience. I didn't find any other place to get help.
I've followed (correctly I think) all steps outlined, but something's go wrong. The RSS links I've get by email don't work.

Here is some tests with some RSS readers, for this following link https://script.google.com/macros/s/AKfycbyMceBFAhYZRLtCo7BeXETlTpjaHEOhPcq0pX-Z8x2c_W04RJo/exec?action=timeline&q=labnol :

• Feedly.com says « No feeds found. If you are looking for a specific site or feed, please enter the full url. » ;
• Liferea says « Could not detect the type of this feed! Please check if the source really points to a resource provided in one of the supported syndication formats! » ;
• Firefox's feed preview ask me to open the file 'echo', which content is « undefined ».

What I missed ?

Thanks for help ! :)
JC