Peter (RL) (2/22/2021)
Unfortunately there is a known issue with the Nvidia 3000 series cards and Iray rendering. Please contact Technical Support using the link below and they will be able to let you have a beta version that should hopefully resolve the problem until a permanent fix is available.
https://www.reallusion.com/CustomerSupport/UserEx/QForm.html
This topic should be pinned somehow as it comes up repeatedly.