How can I troubleshoot a powerline (homeplug) and switch connection?

Due to living in a multistory house, we use powerline (homeplug) adapters, which in principle works fine. We have several restrictions though:

1. All powerline adapters currently in service have only one LAN port/outlet.


2. We don't want to shell out money for a new ">1 LAN-port" powerline adapter, because:


3. I already own a working switch and want to use it.


4. I can't attach the switch to the router, but multiple devices need to be attached to the switch

For these reasons (being on the 2nd/3rd floor with multiple devices), I am forced to connect the (Auto-MDI/MDIX -activated) gigabit switch (TP-Link "TL-SG1005D") to what is probably internally configurated as "outlet" or "agent" by the powerline (devolo "dLAN® 200 AVsmart+") software? Result: It doesn't work.

I wouldn't have to care about all this if I'd use a desktop PC, but:

1. I use a laptop with the above setup, which has only one (Gigabit-)LAN port


2. Buying an expensive laptop docking station just for a 2nd or 3rd LAN port is not an option

Visual network layout: (PLA = powerline adapter)

Troubleshooting/solutions that I tried (unsuccessfully):

3. Obviously I made sure that the powerline adapters are plugged directly in the wall as is advised to do


4. I checked powerline producer website: Adapters are explicitly switch-compatible (but as an agent?..)


5. I e-mailed to the support team of the powerline hardware: Still waiting...


6. I updated the firmware of the powerplugs and checked my own Intel LAN laptop drivers (up to date)


7. The gigabit switch has no firmware update possibility, but I reset its power


8. I deactivated and reactivated my laptop's LAN adapter and tried with a fixed IP


9. I am a 100% sure my GB-switch (still) works, as the transfer (cable and endpoint-wise) between my laptop and my "NAS" (drobo) does indeed work.


10. I searched through Google + SU: Found several existing threadss, but none comparable to my setup.

Bonus question: If I'd alternatively connect my drobo NAS to a - spare - (W)LAN powerline adapter, could other people in the same house (i.e. people that use the same router-connection via powerline!) connect to its contents via the powerline LAN or WLAN as I myself plan to do? Normally people worry about neighbors (which is no problem), but in my case I (have to) worry about the people inside our network.

Answer

Ok, I found my mistake: I had my drobo NAS set to a fixed IP. Letting it receive a DHCP IP solved it.

I had to wait 5-10 minutes though, until all devices got used to the new, proper state.

(Until then, even after my change, both www and my other device didn't yet work concurrently.)

Another two steps I initially forgot to test:

a. Exchanging the devices (and their order) on the switch and b. swapping the dLAN adapters.