The web server does not understand chunked content -> "filtertype required" error

[grololo06]

Seen today:

12:14:22.946989 IP (tos 0x0, ttl 127, id 23919, offset 0, flags [DF], proto TCP (6), length 463)
    172.16.36.47.51597 > ecotaxa.obs-vlfr.fr.http: Flags [P.], cksum 0x98a5 (correct), seq 3514804023:3514804446, ack 3772878237, win 8212, length 423: HTTP, length: 423
	POST http://ecotaxoserver.obs-vlfr.fr/gettaxon/ HTTP/1.1
	Host: ecotaxoserver.obs-vlfr.fr
	User-Agent: python-requests/2.26.0
	Transfer-Encoding: chunked
	Accept: */*
	Accept-Encoding: gzip, deflate
	Connection: keep-alive
	Content-Type: application/x-www-form-urlencoded
	
	8e
	id_instance=9&sharedsecret=ZiAgKGDHiQ4WAj6Gi1RN41WHrMkPut8B3AzgXqLWZ&ecotaxa_version=2.5.11&filtertype=since&startdate=2000-01-01+00%3A00%3A00
12:14:22.946989 IP (tos 0x0, ttl 127, id 23920, offset 0, flags [DF], proto TCP (6), length 45)
...
12:14:22.950716 IP (tos 0x0, ttl 64, id 40632, offset 0, flags [DF], proto TCP (6), length 481)
    ecotaxa.obs-vlfr.fr.http > 172.16.36.47.51597: Flags [P.], cksum 0x035a (incorrect -> 0xd586), seq 3772878237:3772878678, ack 3514804451, win 501, length 441: HTTP, length: 441
	HTTP/1.1 200 OK
	Server: nginx/1.14.0 (Ubuntu)
	Date: Thu, 23 Feb 2023 12:14:22 GMT
	Content-Type: application/json
	Content-Length: 30
	Connection: keep-alive
	Content-Security-Policy: default-src 'self' 'unsafe-inline' 'unsafe-eval' blob: data: cdnjs.cloudflare.com server.arcgisonline.com www.google.com www.gstatic.com www.google-analytics.com cdn.ckeditor.com;frame-ancestors 'self';form-action 'self';
	
	{"msg":"filtertype required"}

For some reason, a standalone EcoTaxa instance sends this request for taxonomy sync, but the full list of parameters is not received.

[grololo06]

The server runs uwsgi 2.0.15

[grololo06]

Exact same client software from another box sends:

 502, options [nop,nop,TS val 1384524849 ecr 924917540], length 0
12:30:58.090558 IP (tos 0x0, ttl 50, id 64913, offset 0, flags [DF], proto TCP (6), length 288)
    lfbn-nic-xxxxxw2-15.abo.wanadoo.fr.46774 > ecotaxa.obs-vlfr.fr.http: Flags [P.], cksum 0x6339 (correct), seq 1677204501:1677204737, ack 198
1269888, win 502, options [nop,nop,TS val 1384524849 ecr 924917540], length 236: HTTP, length: 236
	POST /gettaxon/ HTTP/1.1
	Host: ecotaxoserver.obs-vlfr.fr
	User-Agent: python-requests/2.26.0
	Accept-Encoding: gzip, deflate
	Accept: */*
	Connection: keep-alive
	Content-Length: 165
	Content-Type: application/x-www-form-urlencoded
	

So it might be linked to the sender.

[grololo06]

Can be reproduced with:
$ curl -X POST https://ecotaxoserver.obs-vlfr.fr:443/gettaxon/ -d "id_instance=9&sharedsecret=ZiAgKGDHiQ4WAj6Gi1RN41WHrMkPut8B3AzgXqLWZ&ecotaxa_version=2.5.11&filtertype=since&startdate=2000-01-01+00:00:00" -H "Transfer-Encoding: chunked"
Reply:
{"msg":"filtertype required"}
Either from same-network PC or external one.