Just started WSPR again, and see a nice bright trace at approx 503.965
in the 20:40 slot, but again no decode. I see no-one else reported a
successful decode on WSPRnet at that time either. Looks like still some
problem?

Could it be that the station that does not decode, albeit being received
strong, is not correctly time aligned ? Dimension4 is a very nice tool
for this. And it is also free...

73  Alberto  I2PHD