I'm not a lawyer, but if they had a contract that AWS must provide 30 days notice then it seems like Parler has a case.
"Parler is unable or unwilling to promptly identify and remove this content, which is a violation of our terms of service. We made our concerns known to Parler over a number of weeks and during that time we saw a significant increase in this type of dangerous content, not a decrease, which led to our suspension of their services Sunday evening"
- AWS
Sounds like it was "A number of weeks" so probs 30 days notice.
Fox news is not a credible source of information.
Is that according to CNN?
Some of this claim is by a US (trump appointed) Judge: