Authorization header should not be prefixed for bearer tokens, and should not be set in DiscordRestApiClient constructor if blank (it gets set later).

If using bearer token, connect to regular gateway.

src/Discord.Net.Rest/DiscordRestApiClient.cs

@@ -75,7 +75,8 @@ namespace Discord.API
             RestClient = _restClientProvider(baseUrl);
             RestClient.SetHeader("accept", "*/*");
             RestClient.SetHeader("user-agent", UserAgent);
-            RestClient.SetHeader("authorization", GetPrefixedToken(AuthTokenType, AuthToken));
+            if (!string.IsNullOrEmpty(AuthToken))
+                RestClient.SetHeader("authorization", GetPrefixedToken(AuthTokenType, AuthToken));
         }
         /// <exception cref="ArgumentException">Unknown OAuth token type.</exception>
         internal static string GetPrefixedToken(TokenType tokenType, string token)
@@ -83,7 +84,7 @@ namespace Discord.API
             return tokenType switch
             {
                 TokenType.Bot => $"Bot {token}",
-                TokenType.Bearer => $"Bearer {token}",
+                TokenType.Bearer => $"{token}",  // Bearer tokens are not prefixed
                 _ => throw new ArgumentException(message: "Unknown OAuth token type.", paramName: nameof(tokenType)),
             };
         }

src/Discord.Net.WebSocket/DiscordSocketApiClient.cs

@@ -234,8 +234,16 @@ namespace Discord.API
                 {
                     if (!_isExplicitUrl && _gatewayUrl == null)
                     {
-                        var gatewayResponse = await GetBotGatewayAsync().ConfigureAwait(false);
-                        _gatewayUrl = FormatGatewayUrl(gatewayResponse.Url);
+                        if (AuthTokenType == TokenType.Bot)
+                        {
+                            var gatewayResponse = await GetBotGatewayAsync().ConfigureAwait(false);
+                            _gatewayUrl = FormatGatewayUrl(gatewayResponse.Url);
+                        }
+                        else
+                        {
+                            var gatewayResponse = await GetGatewayAsync().ConfigureAwait(false);
+                            _gatewayUrl = FormatGatewayUrl(gatewayResponse.Url);
+                        }
                     }
 
                     gatewayUrl = _gatewayUrl;