That is because the URL address you submitted as an RSS feed URL is not of the accepted format. The RSS feed must be in an XML format. Any other format will not be accepted, hence, the “URL is not a valid RSS” message.
That is because the URL address you submitted as an RSS feed URL is not of the accepted format. The RSS feed must be in an XML format. Any other format will not be accepted, hence, the “URL is not a valid RSS” message.