Kong/insomnia · error · Error

auth transforming(toPreRequestAuth): unknown auth grant…

Error message

auth transforming(toPreRequestAuth): unknown auth grant type for oauth2: ${inputGrantType}

What it means

Default branch of the OAuth2 grant switch in toPreRequestAuth (reverse mapping): the internal grant 'password'-family value has no counterpart — specifically values other than authorization_code, implicit, password, client_credentials, refresh_token.

Solutions

1. Use one of the five supported internal grant types
2. Avoid custom grant values when constructing auth in scripts

When it happens

Trigger: Thrown at packages/insomnia-scripting-environment/src/objects/auth.ts:701 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Kong/insomnia@d9bb2b0142 (2026-08-26). Data as JSON: /api/errors/8ac31d2b8d294573. Report an issue: GitHub.

Appendix: source

Thrown at packages/insomnia-scripting-environment/src/objects/auth.ts:701

      const grantType = (() => {
        switch (inputGrantType) {
          case 'authorization_code': {
            return auth.usePkce ? 'authorization_code_with_pkce' : 'authorization_code';
          }
          case 'implicit': {
            return 'implicit';
          }
          case 'password': {
            return 'password_credentials';
          }
          case 'client_credentials': {
            return 'client_credentials';
          }
          case 'refresh_token': {
            return 'refresh_token';
          }
          default: {
            throw new Error(
              `auth transforming(toPreRequestAuth): unknown auth grant type for oauth2: ${inputGrantType}`,
            );
          }
        }
      })();

      return {
        type: 'oauth2',
        oauth2: [
          { key: 'disabled', value: auth.disabled ? 'true' : 'false' },

          { key: 'grant_type', value: grantType },
          { key: 'authUrl', value: auth.authorizationUrl || '' },
          { key: 'accessTokenUrl', value: auth.accessTokenUrl || '' },
          { key: 'clientId', value: auth.clientId || '' },
          { key: 'clientSecret', value: auth.clientSecret || '' },
          { key: 'scope', value: auth.scope || '' },

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