Why do my emails go to people's spam folder?

Each email service has their own algorithm to determine spams, so there is no definitive answer on how to prevent your emails from going to spam.

Since smart mails directly come from your email server, sending via ARTERNAL does not increase the chance of your email going to spam. The only exception is when you are on the external server AWS.

What can I do to prevent my emails from going to spam folder?

To prevent your emails going to people's spam folder, there are several things you can do, including avoiding certain keywords, avoiding attaching too many images, asking recipients to whitelist your email, etc. Linked here is an online article for more details.

Another helpful tool is online spam checkers, such as the one linked here. It identifies the spam triggers in your email and estimates how likely your email will go to spam.