I have 2 buckets on the S3 service. I have a lambda function "create-thumbnail" that triggered when an object is created into an original bucket, if it is an image, then resize it and upload it into the resized bucket.
Everything is working fine, but the function doesn't trigger when I upload files more than 4MB on the original bucket.
Function configurations are as follow,

Timeout Limit: 2mins
Memory 10240
Trigger Event type: ObjectCreated (that covers create, put, post, copy and multipart upload complete)
Instead of using the lambda function, I have used some packages on the server and resize the file accordingly and then upload those files on the S3 bucket.
I know this is not a solution to this question, but that's the only solution I found
Thanks to everyone who took their time to investigate this.
AWS S3 lambda function doesn't trigger when upload large file