If the Application URL setting is configured in Settings → General, Overseerr will explicitly set the origin server hostname when connecting to the SMTP host.
Sender Name (optional)
Configure a friendly name for the email sender (e.g., "Overseerr").
Set this to the email address you would like to appear in the "from" field of the email message.
Depending on your email provider, this may need to be an address you own. For example, Gmail requires this to be your actual email address.
Set this to the hostname or IP address of your SMTP host/server.
Set this to a supported port number for your SMTP host. 465 and 587 are commonly used.
In most cases, Use Implicit TLS should be selected for port 465, and Use STARTTLS if available for port 587. Please refer to your email provider's documentations for details on how to configure this setting.
The default value for this setting is Use STARTTLS if available.
SMTP Username & Password
If your account has two-factor authentication enabled, you may need to create an application password instead of using your account password.
Configure these values as appropriate to authenticate with your SMTP host.
PGP Private Key & Password (optional)
Configure these values to enable encrypting and signing of email messages using OpenPGP. Note that individual users must also have their PGP public keys configured in their user settings in order for PGP encryption to be used in messages addressed to them.
When configuring the PGP keys, be sure to keep the entire contents of the key intact. For example, private keys always begin with -----BEGIN PGP PRIVATE KEY BLOCK----- and end with -----END PGP PRIVATE KEY BLOCK-----.