I faced a similar problem but with another casino and it was only specific games. Maybe it has something to do with the provider and some restriction. I also clearly don't know what could trigger that, but certain slot games from other game providers were OK and if there is a restriction, one is not even supposed to be able to launch the game.
Are you facing this problem with only No limit City games? I suggest you can get in touch with both Casinopunkz and Nolimitcity sup[port teams if so