Kibana :Invalid string. Length must be a multiple of 4

Hi everyone,
I'm trying to load data through kibana but i had this error message below :

The response message shows internal server error

can you please provide more details, like how does your dataset look like and steps we can take to reproduce the error ?

I get this error message when trying to display data by clicking on discover

When i inspect the request i found that there are 2 documents that cannot be loaded