"Request timed out" error though rTorrent server is responding

[sensibleish]

Client:

• µTorrent
• qBittorrent
• Transmission
• rTorrent
• Deluge

Client Version:
??? it's a remote seedbox

Operating System:
macOS Ventura 13.1

Application Version:
2.8.3

Description:
Upon trying to connect, after about 3 seconds, ElecTorrent shows error Connection problem: the connection could not be established. Log shows:

main.ts:88 Error: Request timed out
    at server.ts:126
(anonymous) @ main.ts:88
setTimeout (async)
Browser.self.defer @ angular.js:6877
$evalAsync @ angular.js:19560
(anonymous) @ angular.js:17947
scheduleProcessQueue @ angular.js:18116
$$reject @ angular.js:18179
rejectPromise @ angular.js:18173
reject @ angular.js:18239
(anonymous) @ server.ts:152

A few seconds later, this entry appears:

settings.ts:72 Loading settings
/Users/user/Applications/Electorrent.app/Contents/Resources/app.asar/node_modules/@electorrent/xmlrpc/lib/client.js:134 Uncaught TypeError: Cannot read property 'join' of undefined
    at __enrichError (/Users/user/Applications/Electorrent.app/Contents/Resources/app.asar/node_modules/@electorrent/xmlrpc/lib/client.js:134)
    at Client.<anonymous> (/Users/user/Applications/Electorrent.app/Contents/Resources/app.asar/node_modules/@electorrent/xmlrpc/lib/client.js:140)
    at Object.onceWrapper (events.js:422)
    at ClientRequest.emit (events.js:315)
    at HTTPParser.parserOnIncomingClient [as onIncoming] (_http_client.js:641)
    at HTTPParser.parserOnHeadersComplete (_http_common.js:126)
    at TLSSocket.socketOnData (_http_client.js:509)
    at TLSSocket.emit (events.js:315)
    at addChunk (internal/streams/readable.js:309)
    at readableAddChunk (internal/streams/readable.js:284)
__enrichError @ /Users/user/Applications/Electorrent.app/Contents/Resources/app.asar/node_modules/@electorrent/xmlrpc/lib/client.js:134
(anonymous) @ /Users/user/Applications/Electorrent.app/Contents/Resources/app.asar/node_modules/@electorrent/xmlrpc/lib/client.js:140
onceWrapper @ events.js:422
emit @ events.js:315
parserOnIncomingClient @ _http_client.js:641
parserOnHeadersComplete @ _http_common.js:126
socketOnData @ _http_client.js:509
emit @ events.js:315
addChunk @ internal/streams/readable.js:309
readableAddChunk @ internal/streams/readable.js:284
Readable.push @ internal/streams/readable.js:223
onStreamRead @ internal/stream_base_commons.js:188

3 seconds seems too short for this to be a real timeout. I found a workaround by creating a fresh server config, but it used the exact same inputs so I don't know what's different. I still have the original config in Electorrent, if e.g. output from defaults would be useful.