Workmail - Autodiscover and ActiveSync stopped working

Hi, We use to use these facilities to configure mail on Outlook 2013 and Outlook 2016. This has stopped working few weeks ago. The existing email clients (Outlook) stopped receiving emails asking for a password. I have tested it on two different systems and two different versions of Outlook to no avail. I have come across this document: https://docs.aws.amazon.com/workmail/latest/adminguide/autodiscover.html It looks like some configuration is necessary for Autodiscover to work. Not sure if this has been done or not but Autodiscover definitely worked in Outlook and I never had to resort to configure it via ActiveSync (except mobile devices) or IMAP. Our DNS has a CNAME record to point from autodiscover.ourdomain.com to autodiscover.mail.eu-west-1.awsapps.com. We also have records for SPF, DKIM, DMARC and MAIL FROM - all showing green (Verified) in the Workmail control panel. What could impact this? Please advise. Thank you Best regards