How to troubleshoot corporate filters and gateways?

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.