before you start troubleshooting, you need to know which category your problem falls into. different root causes need different fixes, and guessing wastes time.

answer these questions about your current situation:

section A: authentication check

• [ ] have you verified SPF, DKIM, and DMARC records in the last 30 days?
• [ ] are all DNS records pointing to the correct provider (not a previous host)?
• [ ] do you have exactly ONE SPF record per domain (no duplicates)?

if you answered "no" to any of these, your problem is likely authentication. go to chapter 1.

section B: reputation check

• [ ] are your domains less than 4 weeks old?
• [ ] did you skip warmup or warm up for less than 14 days?
• [ ] have you increased sending volume by more than 2x in the last 7 days?
• [ ] is your bounce rate above 3% on recent campaigns?

if you answered "yes" to any of these, your problem is likely sender reputation. go to chapter 2.

section C: throttling check

• [ ] have your open rates dropped gradually over 2-4 weeks (not overnight)?
• [ ] are you seeing normal delivery reports but declining reply rates?
• [ ] do some emails land in Primary while others from the same inbox go to spam?
• [ ] are you sending more than 50 cold emails per inbox per day?

if you answered "yes" to 2 or more of these, you're likely dealing with silent throttling. go to chapter 3.

multiple categories?