The original tutorial used Outlook 2007 and a normal Gmail password in manual SMTP settings. Do not use those screenshots as current authentication instructions. Start with the supported Gmail account-addition route in your actual Outlook version.
Prefer the supported sign-in flow
Choose Gmail when adding the account, sign in through the recognised Google authentication screen and review the requested permissions. Never enter credentials into an unfamiliar page because an email or third-party tutorial sent you there.
If a manual SMTP setup is genuinely required
Use Google’s current settings and check which authentication method your account permits. An app password may be available in some circumstances with two-step verification, but not every account or policy allows one. Do not weaken account security to make an old client connect.
Sending from another address
Using Gmail to send from a different address also requires the appropriate verified sender arrangement. Connecting successfully does not prove the From address is authorised or that every message will reach an inbox. Business-domain mail may need a different service and authentication setup.
Before changing a working account, record its settings and protect any local-only messages. If the problem is an organisation policy or an unsupported mail client, ask the administrator rather than trying random ports and passwords.
Sources and further reading
Guidance checked 26 October 2026: Google’s guidance on Gmail in other email clients.