@Geeksultant & others: The party 'blocking' your mail is *your* email provider.
Any good eMail provider will use a weighting mechanism, combing multiple blocklists that, in the preponderance of evidence, results in an 'Accept', 'Warn', or 'Block'. The 'Warning' conditional acceptance is usually by either altering the Subject line (e.g. by adding 'Possible spam') or by sending the eMail to the spam folder.
It is up to each individual recipients (your) eMail provider to make this determination.
For any blocked messages, you might want to check the status of your current, Microsoft/Outlook eMail MTA:
https://whatismyipaddress.com/blacklist-check
And, just as a point of reference, here is a count of the 11 spams I have seen in the past half-day:
2 Listed at AUTHBL.dq.spamhaus.net
2 Listed at dnsbl.dronebl.org
3 Listed at b.barracudacentral.org
3 Listed at bl.spamcop.net
3 Listed at cbl.abuseat.org
3 Listed at iadb.isipp.com
4 Listed at SBL-XBL.dq.spamhaus.net
7 Listed at bl.mailspike.net
7 Listed at dnsbl-1.uceprotect.net
You will note that SpamCop is right in the middle of the hits count. So don't go blaming an individual BL provider. And that is why a good eMail provider uses multiple BL's in a weighted configuration. If it's only one hit, it's probably not true spam. But more, ???