# The from-address rules that 403 you
Two knowledge-base pages cover this, and together they explain almost every
first-send 403:
1. The test address only sends to yourself. Emails from the default test
address can only go to your own email address. Sending to anyone else gets a
403 telling you to verify a domain and change the from address.
2. Any other from domain must be verified. If the domain in your from address
does not match a verified domain on your account, the API returns a 403
domain-mismatch error.
## Checklist
- Before writing any send code, verify the domain in the dashboard and set the
from address to an address on it. Doing this after the code is written turns
a two-minute setup step into a debugging session.
- When a send 403s, read the error: test-address-to-stranger vs unverified
domain are different fixes. The error text names which one.
- The to address matters too during testing: with the test from address, keep
recipients to your own address until the domain is verified.
- Deliverability starts here as well: a verified domain with proper DNS is
what keeps the email out of spam.