Most of us are using the RSS 2.0 and appending &forumids=XXX to it in order to only receive updates for a specific forum. I, like the others, am experiencing a block.
The RSS feed itself functions - but the 403 error on IFTTT tells me there is a blockage set up to prevent access. Thus, the issue is not the link we are using, but something on the back-end with is blocking IFTTT (and some readers) from accessing the RSS feed
This started on the afternoon or July 12 or the morning of July 13 per my error logging.