I had inserted a conditional formatting in one column. However, when I refresh the data, I have faced another problem. Can you assist me on solving these issues too?
You are simply loading to many rows it seems. Do you really need/want all that data (1.04 Mio records) to land in Excel? If you want to do some further analysis you better consider loading the data as connection only and preferably connect it to the data model or even a standard pivot.
Summarize the data with pivots. Then apply CF or whatever. Making your solution "lighter".