I like 21Casino well enough for several reasons (high RTP, active rep here, reasonable bonuses etc), but TBH when it comes to some providers you may as well just not bother, a lot of the time you'll be doing well to get through 100 autospins without the slot bombing out.
I tend to just stick to NetEnt when I'm playing there now, you can still see the spins happening that on a different provider would cause a disconnect/error, but for some reason the NetEnt integration seems to be more tolerant of the delay/lag, and most of the time will carry on. About 10% of the time you'll get a server error and need to reload the slot. Certainly I can have a NetEnt slot get through hundreds of autoplay spins on a single stretch at 21Casino without too much trouble, which is pie in the sky for many other providers there.
Anything that uses the SG/Blueprint platform (you can tell by the autoplayer config screen) seems to be particularly bad.
