[SR-Users] ACK to 200 OK without to tag

We have a SIP doorstation Grandstream GDS3710. When I connect it via kamailio, it does not setup call correct. Kamailio sends a 200 OK with this to field:         t: <sip:0001@192.168.1.150:5069>;tag=e33a13d3-c18c-4df1-b68f-446e42957de6 Grandstream answers with:         To: <sip:0001@192.168.1.150:5069> As the code follows this example: https://kamailio.org/docs/modules/4.3.x/modules/dispatcher.html#dispatcher.…, it seems obvious that this will fail, as there is not route[WITHINDLG] {     if (has_totag()) { There simply is not to tag. Is this a bug in the grandstream? If so how could that go unnoticed, or is it me who misses something? I have attached the full sip text for the 200OK and the ACK -- -------------------- Med Liberalistiske Hilsner ---------------------- Civilingeniør, Kjeld Flarup - Mit sind er mere åbent end min tegnebog Sofienlundvej 6B, 7560 Hjerm, Tlf: 40 29 41 49 Den ikke akademiske hjemmeside for liberalismen - www.liberalismen.dk