December 2018
If you go into the Mystery Portal and find no players (as I did last night in the UK), go back into your Back Yard, go to the Multiplayer Portal and change the region. Close the Portal and go back to the town hall.
You’ll then have player galore!
December 2018
No all fine today, thanks.
Probably just me playing in the wee small hours, but at least this works for picking up matches in other regions