I have tried RSS Guard and it works perfectly.
I don't know why.
Edit:
Solved: Replace the User-Agent
https://github.com/QuiteRSS/quiterss/issues/1616
Moderators: FranklinDM, Lootyhoof


It's because QuiteRSS doesn't identify itself as its own thing and pretends to be a very old version of Chrome. It got caught in the anti-bot filters I've had to put in place to stave off DDoS attacks on the forum. Because it doesn't present its own useragent string, it's not possible to filter and whitelist on that. You may run into the same problem again in the future as long as it isn't being truthful in its user agent string about being an RSS reader.
