You commented SPAM. Here's the checklist that proves your sending address is yours: three records, a 5-second test, and Google's own page for each one.
Why clean emails still land in spam
Gmail judges the address that sends the email, not only the words in it. Google's filters are machine learning trained on user feedback, and they weigh the IP address, the domains and subdomains, whether bulk senders are authenticated, and what recipients did with your past mail. Marking something as spam or "not spam" is one of the key inputs they learn from. (Google's overview of Gmail's spam filters)
1. The 5-second check
Send an email to yourself from your business address and open it in Gmail. If there is a question mark next to the sender's name or photo, Gmail could not authenticate the message. Google is clear that unauthenticated messages are not necessarily spam, but they are the ones that get marked as spam or rejected. (Google: the question mark on a sender)
For the detail, open the message, click More next to Reply, then Show original. That page shows the authentication results for the message. Look for SPF, DKIM and DMARC, and check each one says PASS. (Google: Show original)
2. The checklist
SPF. A record that lists which servers may send mail for your domain. It helps stop other people impersonating you. How to check it's set: in Show original, the SPF line should say PASS. If it says FAIL, the server that sent the email is not on your domain's list.
DKIM. A digital signature added to each message, so the receiving side can verify it and know the contents were not changed in transit. How to check it's set: in Show original, the DKIM line should say PASS.
DMARC. A record that lets you choose what happens to messages that fail SPF or DKIM. How to check it's set: in Show original, the DMARC line should say PASS.
Google explains all three, with setup steps, on one page: About email authentication methods. The full sender requirements are here: Email sender guidelines.
What Google requires
Every sender: SPF or DKIM.
Bulk senders (more than 5,000 messages a day to Gmail accounts): SPF, DKIM and DMARC, a spam rate under 0.3% (aim for under 0.10%), a TLS connection, and one-click unsubscribe on marketing and subscribed messages.
Messages that are not authenticated might be marked as spam or rejected with a 5.7.26 error. If you send a few hundred emails a week you are not a bulk sender, but set up all three anyway.
3. Reputation basics
Gmail tracks volume and feedback per domain and per IP address. Reputation comes from sending behaviour, and Google rates it Bad, Low, Medium or High:
Bad: email from this domain is almost always marked as spam or rejected.
Low: likely to be marked as spam.
Medium: a history of sending legitimate email, but occasionally sends spam.
High: a history of very low spam rates, and complies with Gmail's sender guidelines.
Messages from senders with a high reputation are more likely to reach the inbox instead of spam. Your spam rate is the share of your messages that land in an engaged recipient's inbox and then get marked as spam by that person. You can see it in Postmaster Tools, Google's free dashboard for senders. (Google: domain and IP reputation)
Do the 5-second check today. If you see a question mark, or a FAIL, send me the Show original text and I'll tell you which record is missing.
Mike
PS: OptiMAX sets up SPF, DKIM and DMARC for local businesses. If you would rather not touch DNS yourself, reach out at optimax-ai.com.