Error (Invalid Character '<' Looking For Beginning Of Value) when trying to use RTL to swap in / swap out

[Crumb5]

Describe the bug
Error (Invalid Character '<' Looking For Beginning Of Value) when trying to use RTL to swap in / swap out

To Reproduce

Steps to reproduce the behavior:

1. Have a local instance of RTL and a remote instance of boltzd
2. Add the remote boltz address and path to admin.macaroon @ /rtl/config/services/boltz
3. Visit /rtl/services/boltz/swapout and click "Start Swap Out"
4. Error appears on RTL and on Boltzd
5. Note: boltzd transactions made on the remote instance via cli DO appear in History table on RTL

Screenshots
RTL:

ERROR
Error Code
500
Error Message
Invalid Character '<' Looking For Beginning Of Value
API URL
./api/boltz/serviceInfo

Boltzd:

[WARN ] RPC request failed: invalid character '<' looking for beginning of value

Your environment

• Version of RTL - (docker) shahanafarooqui/rtl:v0.15.4
• Version of lnd/core lightning/eclair - "version": "v24.11.1",
• Version of btcd, bitcoind, or other backend - Bitcoin Core version 28.1
• Browser & browser version - Firefox v134.0.1
• Operating system (uname -a on *Nix) - Ubuntu Server: 22.04 on local, 24.04 on remote

[0ceanSlim]

I have this same issue. Something is not working right with boltz/cln

I don't see a v1/serviceinfo anywhere in the boltz docs for the api.

If it's using macaroons then it should be using the boltz rest server and not the grpc server. I've been trying to fix the issue so long I've confused myself now... Anyways I don't see any auth configuration for boltz in the example config nor in the cln one. boltz needs a macaroon header auth for rest communication and the grpc needs boltz tls info, Maybe boltz default install folder gives that but i cant tell what's wrong after troubleshooting for a day

boltzcli works fine

user@linux:~$ boltzcli getinfo
{
  "version": "v2.3.7-cc13544",
  "node": "CLN",
  "network": "mainnet",
  "nodePubkey": "*************************",
  "blockHeights": {
    "btc": 883586,
    "liquid": 3249713
  },
  "tenant": {
    "id": "1",
    "name": "admin"
  }
}

RTL-config.json

{
  "port": "3031",
  "defaultNodeIndex": 1,
  "dbDirectoryPath": "/home/user/RTL",
  "SSO": {
    "rtlSSO": 0,
    "rtlCookiePath": "",
    "logoutRedirectLink": ""
  },
  "nodes": [
    {
      "index": 1,
      "lnNode": "Core Lightning Node",
      "lnImplementation": "CLN",
      "authentication": {
        "runePath": "/home/user/.lightning/master-rune",
        "configPath": "/home/user/.lightning/config",
        "boltzMacaroonPath": "/home/user/.boltz/macaroons"
      },
      "settings": {
        "blockExplorerUrl": "https://mempool.space",
        "lnServerUrl": "http://127.0.0.1:3030",
        "userPersona": "OPERATOR",
        "themeMode": "NIGHT",
        "themeColor": "YELLOW",
        "unannouncedChannels": false,
        "logLevel": "INFO",
        "fiatConversion": false,
        "boltzServerUrl": "https://127.0.0.1:9003",
        "enableOffers": false,
        "enablePeerswap": false,
        "bitcoindConfigPath": "/home/user/.bitcoin/bitcoin.conf",
        "channelBackupPath": "/home/user/RTL/channels-backup/node-1",
        "logFile": "/home/user/RTL/logs/RTL-Node-1.log"
      }
    }
  ],
  "multiPassHashed": "*******************************************************"
}

boltz.toml

# Path to the log file
logfile = "debug.log"

# possible values: fatal, error, warn, info, debug, silly
loglevel = "info"

# possible values: "mainnet", "testnet" or "regtest"
network = "mainnet"

# you will have to set this to "cln" or "lnd" if you have configuration values >
node = "CLN"

[BOLTZ]
# By default the daemon automatically connects to the official Boltz Backend fo>
# This value is used to overwrite that
# url = "https://api.boltz.exchange"

[DATABASE]
# Path to the SQLite database file
# path = "~/test.db"

[CLN]
# Host of the gRPC interface of CLN
host = "127.0.0.1"

# Port of the gRPC interface of CLN
port = 8001

# Path to the data directory of CLN
datadir = "~/.lightning"

# Paths to TLS certificates and keys of CLN. Not required if datadir is specifi>
rootcert = "~/.lightning/bitcoin/ca.pem"
privatekey = "~/.lightning/bitcoin/client-key.pem"
certchain =  "~/.lightning/bitcoin/client.pem"

[RPC]
# Host of the gRPC interface
host = "127.0.0.1"

# Port of the gRPC interface
port = 9002

# Whether the REST proxy for the gRPC interface should be disabled
restDisabled = false

# Host of the REST proxy
restHost = "127.0.0.1"

# Port of the REST proxy
restPort = 9003

# Path to the TLS cert for the gRPC and REST interface
tlsCert = ""

# Path to the TLS private key for the gRPC and REST interface
tlsKey = ""

# Whether the macaroon authentication for the gRPC and REST interface should be>
noMacaroons = false

# Path to the admin macaroon for the gRPC and REST interface
adminMacaroonPath = ""

# Path to the read-only macaroon for the gRPC and REST interface
readOnlyMacaroonPath = ""

The log for RTL shows it making a request to the REST server with a GRPC macaroon metadata header. I think this is the issue.

logs

[2/13/2025, 9:30:16 AM] INFO: Boltz => Getting Boltz Information...
[2/13/2025, 9:30:16 AM] INFO: Common => Boltz Options.
[2/13/2025, 9:30:16 AM] INFO: Boltz => Getting List Swaps...
[2/13/2025, 9:30:16 AM] INFO: Common => Boltz Options.
[2/13/2025, 9:30:16 AM] INFO: Boltz => Boltz List Swaps Received.
[2/13/2025, 9:30:16 AM] INFO: Boltz => Boltz Information Received.
[2/13/2025, 9:30:34 AM] INFO: Boltz => Getting Service Information...
[2/13/2025, 9:30:34 AM] INFO: Common => Boltz Options.
[2/13/2025, 9:30:35 AM] ERROR: Boltz => Get Service Information Error: {"name":"StatusCodeError","statusCode":500,"message":"500 - {\"code\":2,\"message\":\"invalid character '<' looking for beginning of value\",\"details\":[]}","error":{"code":2,"message":"invalid character '<' looking for beginning of value","details":[]},"options":{"url":"https://127.0.0.1:9003/v1/serviceinfo","rejectUnauthorized":false,"json":true,"headers":{"Grpc-Metadata-macaroon":"my macaroon is here"},"simple":true,"resolveWithFullResponse":false,"transform2xxOnly":false},"response":{"statusCode":500,"body":{"code":2,"message":"invalid character '<' looking for beginning of value","details":[]},"headers":{"content-type":"application/json","vary":"Origin","date":"Thu, 13 Feb 2025 14:30:35 GMT","content-length":"88","connection":"close"},"request":{"uri":{"protocol":"https:","slashes":true,"auth":null,"host":"127.0.0.1:9003","port":"9003","hostname":"127.0.0.1","hash":null,"search":null,"query":null,"pathname":"/v1/serviceinfo","path":"/v1/serviceinfo","href":"https://127.0.0.1:9003/v1/serviceinfo"},"method":"GET","headers":{"Grpc-Metadata-macaroon":"my macaroon is here","accept":"application/json"}}}}

It gets information and swaps just fine but when I click on a start swap in or out in RTL I get the 500