Ik heb hetzelfde gehad. Na een speurtocht op internet heb ik het volgende gevonden wat bij mij werkte (helaas in het engels):
For some reason those relays must be first reset and the only reset that worked was from the B button (not S1).
So disconnect the power first then hold the B button and then turn on the power while holding down the B button for more than 3 seconds. This process is not very clear in FGS212/222 manuals. After this go through the inclusion process with Homey, Add Device–>Z-wave–>3x press button B (you might get the surprise that soon after you select z-wave, your unit will get included before even pressing 3 times the button. It happened a couple of times in my case for some strage reason) Anyway, when you do this inclusion, I would just select “Z-wave” in Homey and not the specific unit under the Fibaro app (Single Relay 2 in your case) Because in doing this, there is no room for mistake, Homey will find the right device for you as long as the Fibaro app is installed.
If this fails, then try “Remove Device” from Homey and press 3 times B. Then try include it. Homey has this “moods” sometimes like a pregnant woman and although you had no successful inclusion, it will exclude every time a device