I verified that Avira appears to identify ftpupload.net as “spyware/malware”, at least for their router based 3rd party products, whether right or wrong. See related post.
And, I just noticed this:
Avira is part of Gen – a global company with a family of consumer brands, including Norton, Avast, LifeLock, Avira, AVG, Reputation Defender and CCleaner. That might partly explain the confusion of Norton/Avira.