There are dozens of possible causes, the most common ones are ASIO driver settings (most DAW's allow you to customize these in the settings, things to look out for could be your sample rate, buffer size and other options your DAW might provide), adding too many and/or too heavy instruments ('VST's') to your project as I already mentioned earlier, using a sound interface which simply can't cope (using the on-board audio interface which is installed on your computer is usually not a good idea to get the best performance) and of course there are also possible hardware problems (though I guess we can rule those out considering that things work normally in your other DAW). Try to get the buffer length to somewhere near 10 ms (which basically means at 441. Now you need to change the buffer length settings as well.

Navigate to Audio settings and select FL Studio ASIO in the Device drop-down menu. With that I mean that whilst playing the rest of your system can't keep up and that results in those crackling sounds. But if the problem is due to buffer underruns then there are some steps which you need to perform to solve this issue. First to keep in mind is that these kind of instruments are quite heavy when it comes to resource demands, so it is possible that it might overload the DAW (this can theoretically happen if you also have a lot of other resource hungry instruments active). Crackling sounds usually indicate computer / DAW problems somewhere.

Fl studio 12 asio crackling