1. Enable OAuth Settings in Salesforce

Ensure the OAuth and OpenID Connect Settings are configured:

• Go to Setup > Security > OAuth and OpenID Connect Settings.
• Enable the Allow OAuth Username-Password Flows option if using the Username-Password Flow (temporary workaround; see Security Note). The link is available in the OAuth and OpenId Connect (for DEVHUB) settings. (eg. https://irissystems-dev-ed.lightning.force.com/lightning/setup/OauthOidcSettings/home)) OAuth and OpenID Connect Settings

2. Access Login History for Diagnostics

Monitor login attempts for troubleshooting:

• Navigate to Profile > My Personal Information > Login History (User Menu > My Settings > Login History).

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Security Note

The Username-Password Flow is deprecated and less secure. Consider migrating to the Web Server Flow or JWT Bearer Flow for production use. Update the Connected App and code accordingly to avoid future compatibility issues.