We see "Error 1000 - Prohibited IP" after updating DNS to the Cloudflare WAF; what should we do?

This error message is an indicator that your DNS is managed with Cloudflare.  This will cause a conflict if you try to map the DNS to another Cloudflare IP address.  In this case, you will need to "grey cloud" your DNS entry with Cloudflare (set the proxy status on your A record to "DNS Only").  See this article for the detailed instructions:

https://support.imis.com/hc/en-us/articles/4404181198093-We-manage-our-DNS-in-Cloudflare-what-do-we-need-to-do-