In general, avoiding errors in monday formulas can sometimes be tricky.
For example, to eliminate divide by zero errors, something like this would make sense:
IF({number}<>0,1/{number},"")
But this does not work. All portions of the formula must ALWAYS be valid. This DOES work:
IF({number}<>0,1/IF({number}<>0,{number},1),"")
However, I suspect that the issue you are currently experiencing may be related to how you are accessing the board. I ran into a similar situation where one of our users was seeing an error like this when no one else was. The issue was that she was using the “old” version of Microsoft Edge. When we had her update to using the new chrome based version of Edge, everything worked.