I am working on azure search service and created indexer, indexes and skillsets. My system was working for last 2 months but i am getting error for last 3 days when indexer is run . It is giving me this error

I tried to find this error online but there was not any help on this error.
I checked that all my services are in US_EAST region.
As you can see in image it is not giving any error/warning but it is failing each time.
