(Almost) No Data received from HP

[Mc-fry]

Hi guys... I have the following Setup.
ESP8266 with Heishamon and self soldered Level shifter circuit like the linked one in readme File.
Self made shielded cable in cn-nmode connector of J series Heatpump. Cable length is about 50cm.

Heishamon WiFi and Webinterface are working. But i almost never get Data from heatpump. After reboot maybe one or two times it works but then I always get the "0 bytes received" error. I let it run several days, no more data.

Things I tried to troubleshoot:

• Checked Rx tx polarity several times
• measured my wire connectivity
• powered esp on lab bench and created loopback with additional pullup. it received its own data without problem (level shifter works)
• checked heatpump 5v (ok)

What could be the problem here? Is my heatpump transmit circuit broken? Does it lock out because I try to communicate every 5 sec?
Why do rebooting or plugging/unplugging cn-nmode sometimes help for one or two data packages?

Maybe someone can help. Thx!!!

Here is a screenshot of the console

[MiG-41]

For sure bad connection.
Maybe even bad soldering on cn-cntmode socket on PCB ( but that is the last thing).

[IgorYbema]

What esp8266 board are you using? Did you add the gpio5 enable line?