Seadoc accesses seahub not through SEAHUB_SERVICE_URL

Ok, I cou;dn’t stop myself testing it. Second issue is now saving the file back to Seafile. I see in seahub.access.log

- 10.10.10.34 [22/Apr/2025:21:15:33 +0000] "POST /api/v2.1/seadoc/upload-file/55d418e7-1ce7-4847-a0af-f90fa7e1006a/ HTTP/1.1" 500 285 "-" "axios/1.7.4" 0.768

And in sdoc-server.log:

","3":"O","4":"C","5":"T","6":"Y","7":"P","8":"E","9":" ","10":"h","11":"t","12"
:"m","13":"l","14":">","15":"\n","16":"<","17":"h","18":"t","19":"m","20":"l","2
1":" ","22":"l","23":"a","24":"n","25":"g","26":"=","27":"\"","28":"e","29":"n",
"30":"\"","31":">","32":"\n","33":"<","34":"h","35":"e","36":"a","37":"d","38":"
>","39":"\n","40":" ","41":" ","42":" ","43":" ","44":"<","45":"t","4..."283":">","284":"\n","status":500}

I can’t find any explanation about this. Services appear to see each other now. Any ideas what might be wrong?

Update, I parsed this JSON as:

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Page unavailable</title>
</head>
<body>
    <h1>Page unavailable</h1>

    <p>Sorry, but the requested page is unavailable due to a server hiccup.</p>

    <p>Our engineers have been notified, so check back later.</p>
</body>
</html>
500