Very often I can see that users have issues by configuring of export CTS system in HALM. There is actually a very good guide about how to configure HANA for CTS. Nevertheless, it is still one of the most reported issues. I prepared a short video which could help you to configure an export CTS system and possibly to trace the problems (if any). Please, take a look.
Pease be sure that the requirements listed in the note 2097341 are fulfilled, especially regarding roles.
Please also note, that the alias for the Export Web Service point should be specified starting with a slash (i.e. /001/export_cts_ws).
In the case of issues by registering of a CTS system, you could try a very simple tool helping you to diagnose the outgoing HTTP Destination. The tool itself is attached to the mentioned note. The instructions how to use the tool are also attached.
References
[1] Change and Transport System
[2] How To Configure SAP HANA for CTS in SAP HANA S... | SCN