Look up column type in the list gives error

I have 2 lists. List A and List B. Both the lists have a common field EMP ID. I have to create an index to the List B with List A using Lookup type column.

But when I create column in my list, and select Look Up as its type, I'm receiving Error : Unexpected Error Occurred" with some Correlation ID.

How to get rid of this error and proceed with creating relationships with the 2 lists. 

Thanks in advance for any help.