What SMTP settings are needed (e.g. Gmail App Password) and why must From match the sender?

For SMTP sending you typically need the host, port, username, password, and TLS setting of your mail service. With Gmail specifically, you must use an App Password (not the normal account password), since Google blocks basic-auth logins. Crucially, the From address must match the authenticated sender/account — mail providers reject or spam-filter messages whose From doesn't match…

For SMTP sending you typically need the host, port, username, password, and TLS setting of your mail service. With Gmail specifically, you must use an App Password (not the normal account password), since Google blocks basic-auth logins. Crucially, the From address must match the authenticated sender/account — mail providers reject or spam-filter messages whose From doesn't match the sending account (it looks like spoofing). So configure the From to be the same mailbox you authenticate as. *(Exact required fields depend on your provider; confirm against your build's email configuration.)*