How to troubleshoot corporate filters and gateways?

Corporate filter troubleshooting:

Identify the filter:

Headers reveal filter type

Common: Proofpoint, Barracuda, Mimecast, Microsoft Defender

Check relevant blocklists:

Barracuda has its own list

Check corporate-focused lists

Corporate-specific challenges:

Policies vary by company

May block marketing entirely

Admin-configured rules

Options:

Direct contact with recipient to whitelist

Request admin exception

Ensure transactional messages clearly labeled

B2B considerations different from consumer

Corporate harbors have stricter, variable rules. Relationship with the specific company may help.