Recently, one site has been blocked from multiple web-based services. All of the services were using Amazon CloudFront as backend. One by one, when the vendors were contacted, they all found that CloudFront was blocking their site’s external Internet IP. This was happening despite the fact that a large number of blacklist checks were coming up green. Eventually, I found these:
talosintelligence.com/reputation_center
www.apivoid.com/tools/ip-reputation-check/
which do a lot more. Not sure how timely some of the reporting is. And they still did not explain the CloudFront issues.