Fix Cold Email Deliverability

I send roughly 3,000 service-outreach cold emails each day through G Suite (Google Workspace). From launch until January 2025 the campaign generated a steady flow of leads, but since then the reply rate has collapsed and keeps falling.

I’m looking for someone who can quickly identify why my messages are now landing in spam or being throttled, then implement (or guide me through) the steps that will bring reply rates back to—or beyond—the previous level. The content is short, value-focused and currently personalised only with the recipient’s name, so there may be technical and strategic improvements still on the table.

Typical areas I expect you to assess include, but aren’t limited to, domain reputation, SPF/DKIM/DMARC alignment, sending volume patterns, list hygiene, content structure, and possible migration or multichannel routing (e.g. a warmed-up dedicated IP, Mailchimp or SendGrid) if that proves more effective than pushing everything through G Suite.

I’ll fully cooperate with any tests, warm-up sequences or configuration changes you propose, and budget will not be a barrier if your solution demonstrably lifts deliverability and responses. Please outline what diagnostics you would run first and any comparable successes you’ve had so I can move fast on this.