Error when refreshing in PB

Hello, 

I have a report in Power bi, that I use to refresh month by month. Now, after trying to refresh and without doing any changes to my source, I got this message:"a specific column contais a duplicate value and this is not allowed for columns on the one side of a many-to-one relationship or for columns that are used as the primary key of a table".

Now, I am a beginner on Power bi, but to avoid receiving this errorr, I went to the column named in the error and I have removed duplicates, after that, my refresh worked. Do you think is it ok or should I go for another solution? And which one?

Thanks!