OAuth 'Username‑Password Flow Disabled' in Salesforce: What It Means & What to Do

This technical article notes that Salesforce disables the OAuth username‑password flow for security reasons. It explains that orgs created after Summer ’23 have the flow disabled by default and that using it will result in invalid grant errors. The post recommends enabling the flow only for testing and advises using secure alternatives like client credentials, JWT bearer or authorization code flows.