The most common causes, ranked by frequency
- Unauthenticated domain: missing SPF, DKIM, or DMARC, or they're misconfigured.
- You're sending from a public mailbox (@gmail, @hotmail, @yahoo): it can't be authenticated and providers penalize it.
- Low domain or IP reputation from previous problematic sends.
- Poor-quality lists: purchased addresses, old ones, or many inactive contacts.
- Content that triggers filters: misleading subject lines, words like "free" or "urgent," excessive capitalization, a single image with no text.
- No visible unsubscribe link, or unsubscribes not processed in time.
- High hard bounce rates and spam complaint rates.
How to fix it, step by step
- 1
Authenticate your domain
Set up SPF, DKIM, and DMARC. It's the most important step. You'll find the full guide on the how-to-authenticate-your-domain page.
- 2
Use a domain of your own
Never send bulk campaigns from @gmail, @hotmail, or @yahoo. Use a domain of your own, for example [email protected].
- 3
Clean your list
Remove invalid addresses, bounces, and contacts inactive for more than 6 months. arrobaMail automatically purges blocked addresses.
- 4
Warm up the domain if it's new
Increase your sending volume gradually over 4 to 6 weeks to build reputation.
- 5
Review your content
Clear, honest subject lines, a balance of text and images, a visible unsubscribe link, and personalization with the recipient's name.
- 6
Check your reports
In arrobaMail you can review bounces, complaints, and reputation history to spot what's failing in each send.
How arrobaMail helps
Our own sending engine (aMailMTA) applies per-provider traffic shaping, automatic backoff on rejections, and IP warmup to protect your reputation. The panel also assists with SPF/DKIM/DMARC authentication and gives you reports to track bounces, complaints, and reputation history.