Why is Gmail rejecting unauthenticated email from gmail.com due to DMARC policy when sending via Sendgrid?

Marketer from Email Geeks explains that long before DMARC, DKIM, or SPF, it was possible and sometimes advisable for domains to reject “internal” mail from external sources. He suggests that Gmail's policy might be to reject inbound mail using gmail.com in the From: domain if it doesn't pass DMARC validation.

Email marketer from Reddit explains that for DMARC to pass, either SPF or DKIM must align with the 'From' address. If you're sending from Sendgrid but using a 'gmail.com' From address, neither SPF nor DKIM will align, causing DMARC to fail and Gmail to reject the email.

Email marketer from Neil Patel explains that when DMARC fails, it means your email isn't properly authenticated, leading to potential rejection by email providers like Gmail. This happens because the email appears to be spoofed, harming your sender reputation and deliverability.

Email marketer from Postmark explains that the key to passing DMARC is alignment. If you are sending mail using Sendgrid, you need to use a 'From' address that is associated with a domain you control and that you have configured to work with Sendgrid. Otherwise, the DMARC check will fail and the email will likely be rejected or sent to spam.

Email marketer from EasyDMARC explains that to pass DMARC, the domain in the 'From' address must align with either the SPF or DKIM authenticated domain. Sending an email from 'gmail.com' via SendGrid, where SendGrid isn't authorized to send on behalf of Gmail, causes this alignment to fail, leading to DMARC failure and potential rejection.

Marketer from Email Geeks advises to stop sending mail using a domain you do not own or control through servers which are not authorized to send mail for that domain. If you want to send mail using gmail.com, send it through and authenticate via gmails SMTP servers.

Email marketer from Mailjet responds that the best practice is to use your own domain to send emails and properly authenticate it with SPF, DKIM, and DMARC. This confirms that you have permission to send emails on behalf of your domain, preventing them from being rejected.

Marketer from Email Geeks states that technically Gmail can do whatever they want with mail entering their system, especially that which impersonates their own domain. Their DMARC record recommends to other mailbox providers what should be done with mail that doesn't align.

Email marketer from AuthSMTP responds that the recommended approach is to use your own domain for sending email. This allows you to fully control the authentication process. If you try to send from a 'gmail.com' address via SendGrid, you are essentially spoofing, which will result in DMARC failures.

Email marketer from StackOverflow shares that the issue is due to DMARC's alignment requirements. When sending via Sendgrid, and using a Gmail address, the email fails SPF and DKIM. Gmails policy is to reject emails that fail this.

Email marketer from Email Hippo shares that to improve deliverability, send from a domain you control and set up SPF, DKIM, and DMARC correctly. Sending from a 'gmail.com' address through SendGrid is impersonation and will likely be rejected by Gmail.

Email marketer from SparkPost shares that setting up proper DMARC records helps ensure your emails are authenticated correctly. When sending from SendGrid, use a domain you own and configure SPF and DKIM to align with the 'From' address. This will help you pass DMARC checks and avoid being rejected by Gmail.

Expert from Email Geeks states it's generally a bad idea to use a freemail domain for bulk mail, considering it a spam sign. She advises buying a domain and configuring it for commercial bulk mail.

Expert from Spam Resource (John Levine) explains that Gmail is aggressively enforcing DMARC policies, especially regarding emails claiming to be from gmail.com but originating from other sources. Sending from SendGrid using a gmail.com 'From' address fails DMARC checks because SendGrid isn't authorized to send on behalf of Gmail, resulting in rejection.

Expert from Word to the Wise (Laura Atkins) responds that DMARC is explicitly designed to prevent the type of behavior you're describing. It's a way for domain owners (like Gmail) to tell receiving mail servers (other ISPs or corporate email systems) how to handle mail that claims to be from their domain but fails authentication checks (SPF and DKIM). Gmail has a strict DMARC policy to reject unauthorized use of @gmail.com.

Documentation from Google Workspace Admin Help explains that if an email claims to be from your domain but doesn't pass SPF or DKIM checks, DMARC tells receiving servers what to do with it. Gmail may reject these emails if your DMARC policy is set to 'reject' or if it identifies the email as suspicious.

Documentation from DMARC.org explains that DMARC helps prevent email spoofing by allowing domain owners to specify how receiving mail servers should handle unauthenticated emails that appear to be from their domain. Gmail is likely rejecting the emails to protect its users from phishing and spam.

Documentation from Microsoft explains that Sender Policy Framework (SPF) is an email authentication method designed to detect forging sender addresses during the delivery of email. SPF allows administrators to specify which hosts are allowed to send mail from a given domain by creating a specific (TXT) record in the DNS. When Gmail receives mail from sendgrid but that email is claiming to be from @gmail, the SPF check will fail, as Sendgrid servers are not allowed to send from gmail.com

Documentation from SendGrid Support shares that for DMARC to pass, the domain in the 'From' address must align with the domain used for SPF or DKIM. Sending from 'gmail.com' via SendGrid will likely fail DMARC because SendGrid is not authorized to send on behalf of Gmail.

Documentation from RFC Editor (RFC 7489) shares that the DMARC specification describes how email receivers should handle messages that fail authentication checks. Gmail is adhering to this specification by rejecting unauthenticated emails from gmail.com when sent through third-party services like SendGrid.