I've been solo mining with cgminer 3.12.3 and now updated to 4.3.4.
However, the same setup (BITMAIN AntMiner U1) which worked on the earlier version, no longer seems to work on the new. (Startup simply: "cgminer.exe -u blah -p blah -o 127.0.0.1:8332")
Did you tell it which bitcoin address to mine for?
If not read the readme.
Thanks for the tip, but adding --btc-address [insert bitcoin wallet address here] to the command-line does not change the picture. As said, cgminer 3.12.3 worked out of the box with these settings.