Amazon Polly Newscaster Voice not working with "Synthesize to S3 Bucket"

I am trying to get the Amazon Polly Newscaster Voice to work.

My text has 13,000 characters, so as per the AWS console instruction, my "task must be saved to an S3 bucket", as it's longer than 3,000 characters.

I have created an s3 bucket and have configured my s3 task settings to output to the s3 bucket. But when I click on "synthesize to s3", I receive this message - "The input text contains invalid SSML syntax. Fix the SSML syntax, and then try again."

I know that my SSML syntax is correct as I have done two checks.

1. I reduced my text to below 3,000 characters and clicked "Listen to speech". My text was successfully read out in Newscaster style.
2. I reduced my text to below 3,000 characters and clicked "Synthesize to S3". The MP3 audio file which perfectly read out in Newscaster style was saved in my S3 bucket.

This is my SSML syntax

<speak> 
<amazon:domain name="news"> 
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
</amazon:domain> 
</speak>

Am I doing something wrong? Or is this a bug?

Thanks in advance for any assistance.