Troubles with MACL-153M / MA-L

I have a MACL-153M and a MA-L installed in a staircase. There is one ceiling lamp with a incandescent bulb. I used a multimeter to ensure the wiring is correct.

Problem:

• If I (try to) switch the light on using the master dimmer, the bulb goes on for about a second and then goes off. However the indicator LED on the master dimmer stays on.
• If I (try to) switch the light on using the companion dimmer, nothing happens except that the indicator LED on the master dimmer goes on.

I changed bulbs and tested the wires but can not find the reason for this problem.

Anyone any idea?

oh boy... you won't believe it...

After nearly two weeks of changing dimmers, measure voltage, reading wiring schemas, I started to put the lamp apart and found a little label 'max. 14W LED bulb'. I went to the website and found this:

Due to the built-in overheating protection, this lamp can only be used with an energy efficient light bulb, max. 13 watts.

Since I had issues with a not compatible LED first, I wanted to be on the save side and use an incandescent bulb...