soxket.io Failed to load resource

[roughnecks]

Hello,

I'm getting 2 errors in developer console: a "400" at kitchenowl page refresh:

/socket.io/?EIO=4&transport=polling&sid=Hq8UM6LFr_cpRr4CA:1  Failed to load resource: the server responded with a status of 400 ()

And subsequently a "401":

main.dart.js:140311  GET https://kitchen.domain.tld/api/household/1 401 (Unauthorized)
(anonymous) @ main.dart.js:140311
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
$1 @ main.dart.js:58414
TM @ main.dart.js:59526
$0 @ main.dart.js:58890
EA @ main.dart.js:5484
ya @ main.dart.js:58799
$0 @ main.dart.js:58853
clV @ main.dart.js:5516
cmq @ main.dart.js:5518
$1 @ main.dart.js:58361
childList
$1 @ main.dart.js:58368
c0r @ main.dart.js:5523
bJr @ main.dart.js:5616
hr @ main.dart.js:5535
Mv @ main.dart.js:59351
aTk @ main.dart.js:59223
YY @ main.dart.js:59154
kC @ main.dart.js:59332
kC @ main.dart.js:59087
ap_ @ main.dart.js:140364
(anonymous) @ main.dart.js:140291
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
as0 @ main.dart.js:140348
mU @ main.dart.js:140286
(anonymous) @ main.dart.js:140262
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
aT8 @ main.dart.js:140267
DX @ main.dart.js:140253
YJ @ main.dart.js:140254
$0 @ main.dart.js:163487
(anonymous) @ main.dart.js:163125
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
aJW @ main.dart.js:163167
wt @ main.dart.js:163117
Uk @ main.dart.js:163108
aS @ main.dart.js:163109
(anonymous) @ main.dart.js:40078
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
cb0 @ main.dart.js:40087
abt @ main.dart.js:40074
(anonymous) @ main.dart.js:164324
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
bS @ main.dart.js:164361
(anonymous) @ main.dart.js:164160
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
baA @ main.dart.js:164175
xu @ main.dart.js:164142
iY @ main.dart.js:164143
(anonymous) @ main.dart.js:142785
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
a6 @ main.dart.js:142790
Be @ main.dart.js:158082
a1h @ main.dart.js:110839
(anonymous) @ main.dart.js:106874
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
aIF @ main.dart.js:106879
Xq @ main.dart.js:106865
(anonymous) @ main.dart.js:4137
(anonymous) @ main.dart.js:107442
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
aq7 @ main.dart.js:107447
$1 @ main.dart.js:107436
(anonymous) @ main.dart.js:106979
(anonymous) @ main.dart.js:5332
$2 @ main.dart.js:58420
o @ main.dart.js:5318
aqr @ main.dart.js:107002
$2 @ main.dart.js:106974
cp2 @ main.dart.js:1267
me @ main.dart.js:63896
zE @ main.dart.js:63902
aoa @ main.dart.js:63916
tr @ main.dart.js:52134
aTa @ main.dart.js:52291
(anonymous) @ main.dart.js:4137
FB @ main.dart.js:52389
$1 @ main.dart.js:52422
TM @ main.dart.js:59526
$1 @ main.dart.js:59542
ck0 @ main.dart.js:7821
(anonymous) @ main.dart.js:7812

I'm running docker with root but the container's files are owned by a specific user.
This is latest kitchenowl's release on Linux (server docker) and Windows (client chrome).

I wasn't sure if CORS might be at fault, so I tried to add:
add_header Access-Control-Allow-Origin *; to my nginx virtualhost, to no avail.

Thanks