Amazon SES is an email service provider that supports full DMARC compliance for its customers. We've created a guide to provide you with all of the necessary steps and considerations for configuring Amazon SES: https://dmarcian.com/amazon-ses-source-guide/
See our source guide for guidance. Additionally, Amazon SES supports 2048-bit DKIM keys. Consider changing your keys if you are using 1024-bit keys.
Amazon SES requires the use of a dedicated subdomain to achieve SPF alignment. See our source guide for further guidance.