Dynamo DB Read Time out with GSI Keys

Hello Everyone,

I am trying to read 50k records from my dynamo DB using the GSI key which would return max records of size 1Mb and the remaining data will be fetched using the last evaluated key. I am facing read time out error after the first read operation which returns me approx 2.5K records with the below error: "Unable to execute HTTP Request: Read time out"

We have added pagination limit to resolve this issue, could anyone please help me in understanding why we are getting Read time out error while reading the records with GSI.

Note: The dynamo DB is in OnDemand.