I read reviews and even from trusted providers there is feedback like, I paid for a proxy and it does not work. So is it fake? How do you even check if it works or not?
Listen, a provider can have a million of these proxies. Obviously a great provider tries to keep track of everything and only provide proxies that are checked, clean and all that. But there is always a chance that even from a top provider you will get a dead IP.
You can check a proxy with super simple tools like sites that show your current IP and country. And I check if the location matches what the provider claimed. If everything is fine, I try to test it. Actually one of the tasks of a proxy, as it says in the article https://www.brandvm.com/post/in-the-digital-world-online-privacy-and-unlimited-global-access-come-first , is unlimited access to any sites and resources. I try to go where it is usually blocked. If everything mentioned above works, then great.