git-ecosystem/git-credential-manager · error · Trace2Exception

Interactive logon for

Error message

Interactive logon for '{0}' failed.

What it means

After GCM performs an interactive (browser/GUI) GitHub logon to obtain a Personal Access Token, if the token is null or the interactive flow did not produce a usable credential, GeneratePersonalAccessTokenAsync throws this Trace2Exception formatted with the target URI. It signals that the interactive authentication attempt completed without yielding a token.

Solutions

  1. Retry the interactive logon and ensure any requested OAuth authorization (SSO/org access) is completed in the browser.
  2. Fall back to a PAT: create one at github.com/settings/tokens and store it via 'git-credential-manager github login --pat' or 'git credential approve'.
  3. Check organization/SAML policy: authorize GCM's OAuth app for the organization or enable SSO for your token.
  4. Inspect trace logs (GCM_TRACE=1) to see why the token was null after logon.

Example fix

// before (interactive logon returned no token)
git-credential-manager github login

// after (use an explicit PAT)
git-credential-manager github login --pat
// paste a PAT created at https://github.com/settings/tokens
Defensive patterns

Strategy: fallback

Try / catch

try
{
    var cred = await provider.GenerateCredentialAsync(targetUri, modes);
}
catch (Exception ex) when (ex.Message.Contains("Interactive logon for") && ex.Message.Contains("failed"))
{
    // prompt for an explicit PAT and retry with it
}

Prevention

When it happens

Trigger: Calling GitHubHostProvider.GenerateCredentialAsync which routes to GeneratePersonalAccessTokenAsync; the interactive logon (via GitHubAuthentication) returns no token (user completed the dialog path but token was null/empty) for the given targetUri.

Common situations: GitHub login dialogs that report success but fail to mint a PAT (OAuth app restrictions, SAML SSO not authorized, org policies); network failure right after authentication; enterprise/GHE instances rejecting the token request.

Related errors

AI-assisted analysis of git-ecosystem/git-credential-manager@e8ce762cd0 (2026-09-11). Data as JSON: /api/errors/cad2d38923478029. Report an issue: GitHub.

Appendix: source

Thrown at src/GitHub/GitHubHostProvider.cs:399

                if (result.Type == GitHubAuthenticationResultType.Success)
                {
                    _context.Trace.WriteLine($"Token acquisition for '{targetUri}' succeeded.");

                    token = result.Token;
                }
            }

            if (token != null)
            {
                // Resolve the GitHub user handle
                GitHubUserInfo userInfo = await _gitHubApi.GetUserInfoAsync(targetUri, token);

                return new GitCredential(userInfo.Login, token);
            }

            var format = "Interactive logon for '{0}' failed.";
            var message = string.Format(format, targetUri);
            throw new Trace2Exception(_context.Trace2, message, format);
        }

        internal async Task<AuthenticationModes> GetSupportedAuthenticationModesAsync(Uri targetUri)
        {
            // Check for an explicit override for supported authentication modes
            if (_context.Settings.TryGetSetting(
                GitHubConstants.EnvironmentVariables.AuthenticationModes,
                Constants.GitConfiguration.Credential.SectionName, GitHubConstants.GitConfiguration.Credential.AuthenticationModes,
                out string authModesStr))
            {
                if (Enum.TryParse(authModesStr, true, out AuthenticationModes authModes) && authModes != AuthenticationModes.None)
                {
                    _context.Trace.WriteLine($"Supported authentication modes override present: {authModes}");
                    return authModes;
                }
                else
                {
                    _context.Trace.WriteLine($"Invalid value for supported authentication modes override setting: '{authModesStr}'");

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