you did not mention what version of RM11 you might be on
There have been several posts about the change of API and some users did have some minors problems and some had none at all. While there were a handful of users who had more serious complications
Check out New RootsMagic Update (11.1.1)
also other posts – you might need to contact support support.
I was able to download from Ancestry to a new RM11 db and zero problems (over 25K people)
– however that might not be the best options for you.
Kevin