I solved it by compiling the tasmota firmware from the source code where I enabled the "USE_DOMOTICZ".
This should normally work with the standard Tasmota firmware ( https://github.com/arendst/Tasmota/blob ... /BUILDS.md ), but for me it didn't.

Thanks for your response.

I already flashed the Tasmota firmware, is your solution compatible with the Tasmota firmware or only with the original firmware?

Dear acaonweb,

can you please explain how you have solved this problem?

Thanks in advance.