Hello Igor, I think there are some core extensions necessary before this can be implemented in the module. Federico started to work on that one: https://github.com/kamailio/kamailio/pull/2132 Cheers, Henning -- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.com Kamailio Merchandising – https://skalatan.de/merchandising *From:* sr-users &lt;sr-users-bounces(a)lists.kamailio.org&gt; *On Behalf Of *Igor Olhovskiy *Sent:* Thursday, November 14, 2019 7:41 PM *To:* Kamailio (SER) - Users Mailing List &lt;sr-users(a)lists.kamailio.org&gt; *Subject:* [SR-Users] http_async_client and HTTP2 HI! Seems to be, http_async client is not compatible with http2 servers. I'm having like kamailio_1 | 15(20) INFO: http_async_client [http_multi.c:238]: debug_cb(): [cURL] Connection #0 to host relay-api.pbxservice.com left intact kamailio_1 | 15(20) ERROR: <core> [core/parser/parse_fline.c:264]: parse_first_line(): parse_first_line: bad message (offset: 11) kamailio_1 | 15(20) ERROR: <core> [core/parser/msg_parser.c:681]: parse_msg(): ERROR: parse_msg: message=<HTTP/2 404 kamailio_1 | date: Thu, 14 Nov 2019 18:31:34 GMT .... kamailio_1 | 15(20) ERROR: <core> [core/parser/msg_parser.c:337]: parse_headers(): bad header field [(null)] kamailio_1 | 15(20) ERROR: <core> [core/parser/msg_parser.c:1274]: get_body(): failed to parse to end of headers But plain http_client worked good (not async for sure) kamailio 5.3.0 -- Best regards, Igor _______________________________________________ Kamailio (SER) - Users Mailing List sr-users(a)lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users