Vade Secure is "a global leader in predictive email defense, protecting 600 million mailboxes in 76 countries. We help MSPs and SMBs protect their Office 365 users from advanced email threats, including phishing, spear phishing, and malware."
Based in France, they were originally called "Vade Retro" until 2016. One assumes that perhaps their original name was inspired by "Vade Retro Satana," a latin term that means, basically, "Step back, Satan!"
They offer something called Vade Secure for Office 365, which provides "native, AI-based Email Security for Office 365," meant to block "phishing, spear phishing and malware attacks." It's positioned as a next level filter, meant to provide additional protection beyond Office 365's existing security and anti-spam functionality.
Large American cable modem provider Comcast uses Vade Retro's "Vade Threat List" (VTL) as one of their many email filtering tools. If your sending IP address is listed on the VTL, your mail to comcast.net subscribers is likely to be rejected with an SMTP 5xx error code referencing BL001000 or BL001001.
To request removal from the Vade Threat List, visit abuse.vadesecure.com and fill out the form.
It's unclear to me whether or not this VTL list works in a manner similar to the filters Vade Secure has in place at Orange, SFR, and Laposte.net, as announced back in 2015. I can't find any explicit references to the VTL other than the Comcast blocking information page. It seems possible that perhaps the VTL is a subset of Vade Secure reputation data published in a DNSBL-like format to make it simple for Comcast to utilize.