Calculate field tool fails to copy data from field to field

[abdullahqasrawi]

I used (calculate field tool) to copy the values in (BlockNumber_02) filed to new field (test) that contain Null values but I found that (calculate field tool) fails to do this as the screenshot below

What might be the issue here?

Best

Abdullah

[JayantaPoddar]

Just write [BlockNumber_02] in the expression. Remove the "[test] = " from the expression.