In https://github.com/matomo-org/matomo/issues/9840#issuecomment-188206177 @tsteur said, that it is normal that the RSS feature does not work, but I do not buy this.
Error: RSS feeds can be generated for one specific website &idSite=X. Please specify only one idSite or consider using &format=XML instead.
There is definitely an
idSite=7 present in the url. This is also shown when you change the id to 1. It than tells you:
Error: You can't access this resource as it requires 'view' access for the website id = 1.
The error message might be a bit missleading. RSS renderer can't currently be used for API calls returning multiple datatables (range requests) or results not indexed by date. See https://github.com/matomo-org/matomo/blob/3.x-dev/core/DataTable/Renderer/Rss.php#L46-L51
Not sure if some of that restrictions could be removed. I've you are keen to check that @fdellwing, feel free and do ahead :slightly_smiling_face: