|1and1 finally add SRV records to the DNS|
So login to 1and1 and go to the new Domain Centre, choose your domain and click Edit DNS Settings. At the bottom under 'TXT, SPF and SRV Records' click Add Record. It looks like this picture.
The standard advice is to create a record with this info:
Port Number: 443
However if you add _autodiscover you'll get an error ...