Basically, yes. Short list of providers is mentioned Here
Hard to say. Some common reasons are:
- The specific ip has been used in the past to send spam
- The provider has a bad reputation for reacting to abuse reports, and gets its whole subnet blocked
- You’re on a residential internet connection
You can check with Spamhaus if your ip is blocked. On that page you can also request an unblock if it’s possible.
I would recommend to check multiple blacklists. If your ip is on many blacklists, it might be easier to request a new ip or switch provider. It might take you some effort to get your ip cleaned off of those blacklists.