Same problem here.
New MLM vendor daemon, new FlexLM lmgrd/lmutil 188.8.131.52 and new R2019b licensefile, but no go.
(lmgrd) MLM exited with status 1 signal = 17
(lmgrd) Since this is an unknown status, license server manager will attempt to re-start the vendor daemon
and it just keep repeating itself.
If I do an lmstat I get "Network connect to THIS_HOST failed (-95, 378).
Had to rollback to earlier version R2019a :/