TechnitiumSoftware/DnsServer · error · InvalidDataException

Unexpected URL format: {jsonUrl.ValueKind}

Error message

Unexpected URL format: {jsonUrl.ValueKind}

What it means

Thrown by the AdvancedBlockingApp UrlEntry constructor when building the per-URL list. The code switches on jsonUrl.ValueKind and only accepts String (a bare URL string) and Object (a URL object with url/blockAsNxDomain/blockingAddresses). Any other JSON value kind hits the default branch and raises InvalidDataException. This indicates a structurally malformed block/allow list entry in the config.

Source

Thrown at Apps/AdvancedBlockingApp/App.cs:797

                                            aaaaRecords.Add(new DnsAAAARecordData(address));
                                            break;
                                    }
                                }
                            }

                            _aRecords = aRecords.Count > 0 ? aRecords : group.ARecords;
                            _aaaaRecords = aaaaRecords.Count > 0 ? aaaaRecords : group.AAAARecords;
                        }
                        else
                        {
                            _aRecords = group.ARecords;
                            _aaaaRecords = group.AAAARecords;
                        }

                        break;

                    default:
                        throw new InvalidDataException("Unexpected URL format: " + jsonUrl.ValueKind);
                }
            }

            #endregion

            #region properties

            public Uri? Uri
            { get { return _uri; } }

            public bool BlockAsNxDomain
            { get { return _blockAsNxDomain; } }

            public List<DnsARecordData> ARecords
            { get { return _aRecords; } }

            public List<DnsAAAARecordData> AAAARecords
            { get { return _aaaaRecords; } }

View on GitHub (pinned to d0484b6c1e)

Solutions

1. Inspect the block/allow/regex/adblock list arrays in dnsApp.config and make every entry either a quoted URL string or a {"url": "..."} object.
2. Run the JSON through a linter/validator to locate the non-string/non-object element; the ValueKind reported (Number/Array/etc.) identifies the mistake.
3. Regenerate the list entry from the web UI to guarantee the correct shape.

Example fix

// before (dnsApp.config)
"blockLists": [ https://example.com/list.txt ]
// after
"blockLists": [ "https://example.com/list.txt" ]

foreach (JsonElement urlEntry in blockListsArray.EnumerateArray())
{
    if (urlEntry.ValueKind != JsonValueKind.String && urlEntry.ValueKind != JsonValueKind.Object)
        throw new FormatException($"Block list entry must be a URL string or a {{\"url\":...}} object, got {urlEntry.ValueKind}.");
}

static bool IsValidUrlEntry(JsonElement e) => e.ValueKind == JsonValueKind.String || e.ValueKind == JsonValueKind.Object;

When it happens

Trigger: A URL list entry that is a JSON number, array, boolean, or null instead of a string or object, e.g. '"blockLists": [ 12345 ]' or '"blockLists": [ ["http://x/y"] ]'. Passing a quoted-but-empty or wrong-typed element triggers it.

Common situations: Hand-editing the block list array and dropping the quotes around a URL, wrapping a URL in extra brackets, or pasting a numeric flag where a URL was expected; corrupt config import.

Related errors

• Local end point group map contains an invalid end point: {lo
• Network group map contains an invalid network address: {netw
• Groups array was not defined.
• Forwarder was not defined: {forwarderName}
• No 'forwarderAddresses' were configured.

AI-assisted analysis of TechnitiumSoftware/DnsServer@d0484b6c1e (2026-08-13). Data as JSON: /api/errors/2ed363524a4a24b5. Report an issue: GitHub.