> how do you know that?
Just sent a IKE_SA_INIT Initiator Request to 184.108.40.206 on port 500, got an IKE_SA_INIT Responder Response. So there is something at this address able to reply to IKE requests.
> But first I want to know if teltonika is in fact incompatible with home router of tp-link TL-MR6400
Nothing indicates that this is the case (at least yet).
EDIT: According to the User's Guide of the TL-MR6400 Rev 5.0.0, this router is able to handle OpenVPN and PPTP, and IPSEC is not mentioned. So use one of the former protocols instead of IPSEC.