SLM Server Does Not Respond

I have installed a new WP instance, disabled all the plugins and installed and activated the SLM plugin.
I can manually create a license.
I have also built a client application/plugin on another WP site that tries to activate a license.
The client sends the following to the SLM server:
array(5) { [“slm_action”]=> string(12) “slm_activate” [“secret_key”]=> string(23) “55c13c6a96e5e6.48579819” [“license_key”]=> string(12) “55c13e1dc4dec” [“registered_domain”]=> string(9) “xxxxx.xxx” [“item_reference”]=> string(12) “xxxxxxxxxxxx” }
The server responds with the home page of the WP where the SLM server is installed (as per the selected theme).
There is nothing in the debug log of the SLM server.
Am I missing a step?
Would appreciate any help.
Regards,
Milos

https://ww.wp.xz.cn/plugins/software-license-manager/