diff --git a/PrivaPub.Tests/Infrastructure/FederationHttpTests.cs b/PrivaPub.Tests/Infrastructure/FederationHttpTests.cs
index b4958c9..640f3fb 100644
--- a/PrivaPub.Tests/Infrastructure/FederationHttpTests.cs
+++ b/PrivaPub.Tests/Infrastructure/FederationHttpTests.cs
@@ -27,6 +27,12 @@ namespace PrivaPub.Tests.Infrastructure
 			_peer.MapGet("/big", () => Results.Text("{\"a\":\"" + new string('a', FederationHttp.MaxResponseBytes) + "\"}", "application/activity+json"));
 			_peer.MapGet("/hop/{n:int}", (int n) => Results.Redirect(n == 0 ? "/actor" : $"/hop/{n - 1}"));
 			_peer.MapGet("/gone", () => Results.StatusCode(410));
+			// Mobilizon's NodeInfo: a profile URL left unquoted, which .NET cannot parse as a media type
+			_peer.MapGet("/nodeinfo", (HttpContext context) =>
+			{
+				context.Response.Headers.ContentType = "application/json; profile=http://nodeinfo.diaspora.software/ns/schema/2.1#; charset=utf-8";
+				return context.Response.WriteAsync("{\"software\":{\"name\":\"Mobilizon\"}}");
+			});
 			await _peer.StartAsync();
 			_base = _peer.Urls.First();
 		}
@@ -64,6 +70,13 @@ namespace PrivaPub.Tests.Infrastructure
 		public async Task Refuses_a_fourth_redirect() =>
 			Assert.Null(await Client().GetJson($"{_base}/hop/3", "application/activity+json", default, TestContext.Current.CancellationToken));
 
+		[Fact]
+		public async Task Reads_json_under_a_content_type_dotnet_cannot_parse()
+		{
+			using var fetched = await Client().GetJson($"{_base}/nodeinfo", "application/json", default, TestContext.Current.CancellationToken);
+			Assert.Equal("Mobilizon", fetched.Root.GetProperty("software").GetProperty("name").GetString());
+		}
+
 		[Fact]
 		public async Task Refuses_html() =>
 			Assert.Null(await Client().GetJson($"{_base}/html", "application/activity+json", default, TestContext.Current.CancellationToken));
diff --git a/PrivaPub.Tests/Statistics/DescribeTests.cs b/PrivaPub.Tests/Statistics/DescribeTests.cs
index b34220e..b4de430 100644
--- a/PrivaPub.Tests/Statistics/DescribeTests.cs
+++ b/PrivaPub.Tests/Statistics/DescribeTests.cs
@@ -44,6 +44,8 @@ namespace PrivaPub.Tests.Statistics
 			Assert.Equal(7, facts.LocalComments);
 			Assert.Equal(new[] { "en", "de" }, facts.Languages);
 			Assert.Null(InstanceDocuments.NodeInfo(Json("{}"), "2.0").UsersTotal);
+			// NodeInfo wants the name in lower case, which Mobilizon does not keep
+			Assert.Equal("mobilizon", InstanceDocuments.NodeInfo(Json("""{"software":{"name":"Mobilizon"}}"""), "2.1").Software);
 		}
 
 		[Fact]
diff --git a/PrivaPub/Federation/Objects/InstanceDocuments.cs b/PrivaPub/Federation/Objects/InstanceDocuments.cs
index b51f6ea..997b234 100644
--- a/PrivaPub/Federation/Objects/InstanceDocuments.cs
+++ b/PrivaPub/Federation/Objects/InstanceDocuments.cs
@@ -47,9 +47,10 @@ namespace PrivaPub.Federation.Objects
 			var usage = Section(root, "usage");
 			var users = Section(usage, "users");
 			var metadata = Section(root, "metadata");
+			// (NodeInfo wants the name in lower case; Mobilizon says "Mobilizon")
 			return new NodeInfoFacts(
 				version,
-				Text(software, "name", 200),
+				Text(software, "name", 200)?.ToLowerInvariant(),
 				Text(software, "version", 200),
 				Text(metadata, "nodeName", 200),
 				Plain(Text(metadata, "nodeDescription", 2000), 500),
diff --git a/PrivaPub/Infrastructure/Http/FederationHttp.cs b/PrivaPub/Infrastructure/Http/FederationHttp.cs
index 1aa03e8..ddf8e57 100644
--- a/PrivaPub/Infrastructure/Http/FederationHttp.cs
+++ b/PrivaPub/Infrastructure/Http/FederationHttp.cs
@@ -218,7 +218,7 @@ namespace PrivaPub.Infrastructure.Http
 						exchange.Refused(StatusReason(response));
 						return items;
 					}
-					var mediaType = response.Content.Headers.ContentType?.MediaType;
+					var mediaType = MediaType(response.Content.Headers);
 					if (mediaType == default || !JsonMediaTypes.Contains(mediaType, StringComparer.OrdinalIgnoreCase))
 					{
 						exchange.Refused("content-type");
@@ -356,7 +356,7 @@ namespace PrivaPub.Infrastructure.Http
 						return Refuse(negativeKey, url, $"status {(int)response.StatusCode}", exchange, StatusReason(response),
 							transient: (int)response.StatusCode is >= 500 or 429 or 408);
 
-					var mediaType = response.Content.Headers.ContentType?.MediaType;
+					var mediaType = MediaType(response.Content.Headers);
 					if (mediaType == default || !JsonMediaTypes.Contains(mediaType, StringComparer.OrdinalIgnoreCase))
 						return Refuse(negativeKey, url, $"content type '{mediaType}'", exchange, "content-type");
 					if (response.Content.Headers.ContentLength > MaxResponseBytes)
@@ -629,6 +629,11 @@ namespace PrivaPub.Infrastructure.Http
 
 		static string NegativeKey(Uri target) => "federation-http:refused:" + target.AbsoluteUri;
 
+		// the media type, also from a header .NET cannot parse: Mobilizon's NodeInfo leaves its profile URL unquoted
+		static string MediaType(System.Net.Http.Headers.HttpContentHeaders headers) =>
+			headers.ContentType?.MediaType
+			?? (headers.NonValidated.TryGetValues("Content-Type", out var raw) ? raw.ToString().Split(';')[0].Trim() : default);
+
 		sealed record Refusal(bool Transient, int Status);
 
 		FetchedJson Refuse(string negativeKey, string url, string reason, Exchange exchange, string code, bool transient = false)