no problem is found on my side and I can post the data to my server:
AT+KHTTPCFG=1,"123.123.123.123",80,0
+KHTTPCFG: 1
OK
+KCNX_IND: 1,6
+KCNX_IND: 1,1,0
+KHTTP_IND: 1,1
AT+KHTTPHEADER=1
CONNECT
Content-Length: 25<CR+LF>
--EOF--Pattern--
OK
AT+KHTTPPOST=1,,"/post_put.php"
CONNECT
//here I enter 25 bytes: 1234512345123451234512345
HTTP/1.1 201 Created
date: Wed, 20 Sep 2023 14:27:52 GMT
server: Apache/2.4.41 (Win64) OpenSSL/1.1.1c PHP/7.3.10
x-powered-by: PHP/7.3.10
content-length: 0
content-type: text/html; charset=UTF-8
--EOF--Pattern--
OK
+KHTTP_IND: 1,3,25,201,"Created"
+KCNX_IND: 1,5,30
+KHTTP_ERROR: 1,5
+KHTTP_IND: 1,0
ati3
HL7812.5.4.10.0
OK