Why do I get an unexpected character error when loading .json files in R

I am trying to load a local json file in R. I am using a package called Sofia that includes the json library. I also tried other packages like rjson and the RJSONIO packages but I get the same error (error in ProcessFiles(File=File), unexpected character E.

This is example code when I use the a local package Sofia:

data<-ProcessFiles(file="data1.json",method="Sofia.method")

When I apply the same package to some old .json files it works normally without error. I tried to change the encoding of the file to UTF-8 but the error persists. The file encoding is ANSI Can anybody help with this?