I wouldn’t suggest you use a free Gmail account, you’re better using a Google Workspace (GSuite) account with your domain email. You also need to setup SPF, DKIM and DMARC records. This applies to both transactional emails (purchase confirmations, welcome emails, etc) and marketing emails (newsletters).This guide will show you how to set up SPF, DKIM and DMARC https://www.helloinbox.email/
The suggestion to use an authenticated domain / google workspace rather than @gmail is a good one – although depending on your use case may not be necessary.
Spam is essentially determined via a points system. When the algorithm thinks your score is high enough the email goes to spam. Not all offenses are equal.
Do you know it’s going to spam for others? not just you? One reason it would go to spam if you’re testing by sending to yourself in gmail “from” the same gmail but via Airtable. Gmail knows the origin of the email sent to your email by Airtable is not your email, so it is more likely to send the email to spam. If you’re doing this, try sending to an alternate email address you have access to in order to see if you sending to your exact email is the issue. Also, if the contents of the email has spam trigger words, ALL CAPS, dollar signs $$$$$, !!! lots of .bit.ly links or link redirects, links that display as one thing but take you to a different place on thee internet etc., does it mention a username/password?, any of these in combination could also create a problem.
Since you already have a received email, you should be able to get an idea of the issue. I would take 30 seconds to do two things:
1. to check to see if SPF, DKIM, and DMARC is the problem. Go to the email you received in gmail and open it. Click on thee three dots in the right corner and then “Show Original”
Do you see anything other than PASS for each SPF, DKIM, and DMARC? If yes not great, but one more thing to check.
2. Check if the IP address is the problem.
Copy the IP address after the letters IP (this is the location of where the email originated (airtable)
Click "Click to Check Blacklist Status. If you see lots of red the IP address is the problem. It was all fine in my case, no blacklists.
If you find yourself launching emails at organizations in the future, and you’re sending from Airtable or an Email Service Provider, if you don’t whitelist the “from” email address, your emails will likely be marked as spam by your organizations email server. To the receiving email server (outlook, gmail, etc) at your organization, it looks like someone is trying to pretend they are within your organization when they really are not. To avoid embarrassment make sure SPF, DKIM and DMARC are passing for your sending domain AND whitelist the from email address. To be clear the whitelist is to prevent emails internally at your organization from being marked as suspicious / phishing to people within your organization.
I hope this helps! Curious to know what the problem is…