Let me take some time to give you the reason for that,
First still is the IP address
lots of guys only care about changed IP or not, but do not note WebRTC and DNS leak!
https://ipleak.net https://whoer.net
Also, residential IPs get more trusted than datacenter IPs, You can learn more from here, Do not take much time for IP here,
Second, about browser fingerprint,
There are lots of browser fingerprint use different technology, one of most common is the canvas fingerprinting that others already noted, I suggest you easily check this website,
https://browserleaks.com/
Yes, Now you learn the reason why got suspicious, Okay, assume your IP address is 100% fine, If the issue is browser fingerprint, how to bypass?
There are 2 ways,
One is old ways, Clear cookie and hides all information as you wanted... just as you did
But It's not the best, why?
Let Facebook as a sample, those Data-driven companies already have you so much data...even you're not surfing for their website...
So. nowadays, mainly use spoof ways to prevent browser fingerprinting,
You check this post to learn more,
https://www.bestproxyreviews.com/how...ingerprinting/
So, not just spoof your fingerprinting, for big data company like Facebook, google, amazon, find some related website (interest related) to surf at first, implant your cookie and browsing history at first, then they give you a "user portrait", then not suspicious anymore