I don't remember exactly maybe before Feb 2020, I was running a simulation in RStudio web and it supposed to take 7-8 hours and it ran successfully even when I closed the tab on my computer. After 12 hours I open RStudio and see the result is there. I loved the RStudio web so much and done similar simulations without any problem.
After that time, once I found that there is a server problem in the cloud and you guys fixed it within 6 hours. But after this problem my life in RStudio became hell. The same simulation is getting crashed most of the time. I don't know what happened but I have lost my hope on RStudio Web.
Free accounts on RStudio Cloud ar limited to 1GB RAM memory, this makes memory-intensive tasks prone to brake because of lack of memory, try to modify your code to release as much memory as possible among steps.