Hi everybody

I'm writting a thesis in word, where i'm using the same author (internet source) many times. But there are many different sources from this author. Now in the list of literatur all the sources are listed but for the same year and same author there are coming twice a, but no g, like author (2019a), author (2019b) .. author (2019k) and then again author (2019a), even as its the same author and year. Does someone know what i'm doing wrong?

Thanks for your help