Is the wifi extender powerline device plugged in the gardenhouse? How far between them? or you may try to change the wireless channel on the wifi extender.

Hello,i have the Power Adapter directly connected via LAN cable and a own power socket in House A.The wireless power adapter is in the garden house B. Between them i expect a distance in cable routing length of approx. 200mNote House A is a Farm House from the early 80's, the electrical routing runs to a sub-seperation/fuse box near the stables, from there it runs to the Gard.House.The Wifi range from the router (fritzbox) ends near to the garden housse, thats why i'm ask if there is the posibilty to extend/strengthen the DLAN signalthanks in advance..

It's probably that extra separation/fusebox that ruins the signal, but even if it wouldn't, 200 meters out in the open is literally stretching the maximum range for PLC. If this is three-wire cabling, you might get better results with AV1200 gear. But anyhow, in your case, I'd go with a WLAN repeater plugged in somewhere mid-distance.

really a wifi extender? is there not something like a dlan entender or similar thing...how i can strngth the dlan signal ?

The only thing you can do there is improve your power wiring, or run a LAN cable as far as you can, e.g. to the stable. Run a PLC stretch from behind that extra fusebox to the shed. When installing PLC in close proximity to fuseboxes, consider devolo's DIN-rail 1200 PLC. These wire directly inside the fusebox, on up to three phases, and usually bring a massive improvement to PLC quality. Caution: Needs a trained/certified electrician to install.