Thanks @Alexandre. - I already linked your thread in the very first contact with TP-link support- I though that just X20-DSL was not covered/listed and it will be a quick fix for known bug - but not...

@amtrakuk Thank you for yyour feedback. I have tested many many many diffrent scenarios... including suggested by you. Even on the list the reservation looks fine the device is not reciving...

@naelgh I have the same issue with X20 ( X20-DSL FW1.013 Build 20231226 Rel. 64412 , 2x X20 (v3) FW 1.1.8 Build 20240119 Rel. 37701) Probably the problem is related to network ip from 192.168.0.xx to...