WarmupBay
Guides for getting your emails delivered
Warmup, authentication, spam problems and sending limits, explained without the jargon and checked against what Google, Microsoft and the standards actually say.
Warmup basics
Warmup basics
Back from a break: do you need to warm up again?
A few days off change nothing. After a month of silence, restart low and rebuild in one to two weeks. What is documented, and a step-by-step way back.
7 min read
Warmup basics
How long does email warmup take?
Two to four weeks for a new domain, less for a new mailbox on an old one. What Google and Microsoft actually publish, and how to tell you are ready.
9 min read
Authentication
Authentication
DMARC fails although SPF and DKIM pass
SPF and DKIM pass, DMARC still fails: they passed for a domain that is not in your From address. How to read the header and fix it at the sender.
9 min read
Authentication
No DMARC record found: the one line your domain is missing
No DMARC record found means one TXT record is missing. The exact line to add at _dmarc, how to check it, and whether a small sender needs it at all.
10 min read
Spam troubleshooting
Spam troubleshooting
How to read email headers when a message lands in spam
Open the raw headers in Gmail, Outlook or Yahoo, find the lines that matter, and see what each provider reveals about why your message was filed as spam.
10 min read
Spam troubleshooting
SPF, DKIM and DMARC pass, but the email still lands in spam
Authentication only proves who you are. Six other causes of spam placement, in the order to check them, and how to spot each at Gmail, Outlook and Yahoo.
10 min read
Mail providers
Mail providers
Gmail app passwords: why the option is missing and how to get it back
Google hides app passwords in four situations. How to tell which one applies to your Gmail or Google Workspace account, and what to change.
9 min read
Mail providers
Gmail rejects your app password: what the error means and what to check
Why Gmail answers an app password with Username and Password not accepted, what errors 535-5.7.8 and 534-5.7.9 mean, and six checks to fix it.
8 min read
Sending volume
Sending volume
How many cold emails can one inbox send per day?
Google allows 2,000 emails a day; outreach tools advise 25 to 200. Which numbers are official limits, which are convention, and how to choose yours.
10 min read
Sending volume
Secondary domains for cold email: what they protect, and what they don't
A second domain keeps cold email complaints off your main one, but only in part. What providers document, inboxes per domain, and the setup steps.
8 min read
Choosing a tool
Choosing a tool
Free email warmup tools: what is actually free
We checked 20 email warmup tools against their own pricing pages on 5 October 2026: which have a real free plan, which are trials, and which cost money.
12 min read
Choosing a tool
How a warmup pool works, seen from inside your mailbox
What a warmup pool is, who is in it, what the tool does inside your mailbox and what access you hand over. With eight questions to ask before you join one.
9 min read
Choosing a tool
Is email warmup allowed? What Google and Microsoft have put in writing
Is warmup against Google's terms of service? The exact clauses from Google and Microsoft, what Google enforced in 2023, and where the risk lies.
10 min read