Unable to deploy new code on EBS

Would it possible you have reached Elastic Beanstalk application version quota for your account and region? Default quota is 1000 versions across all applications. This can be increased, but better alternative might be deleting old version and configure lifecycle policy.

• EB quotas; https://docs.aws.amazon.com/general/latest/gr/elasticbeanstalk.html
• Managing EB application versions; https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/applications-versions.html