Cannot access Syncloud.it server due to ERR_CERT_COMMON_NAME_INVALID

Syncloud.it
4
  1. can I use domain that is also used for other service (i.e. Tutanota email)?

As I know mail provider would want you to prove that you own the domain name by adding additional dns records (which is not automated at the moment), we had an experiment recently with a personal domain: DNS Records TXT

I think there are multiple options:

  1. Your domain + 3rd party Mail UI/Server
  2. Your domain, Mail UI + 3rd party smtp server (no spam issue)
  3. Your domain, Mail UI, send directly (spam issue) (current Syncloud Mail)
  1. Would the subscription price be the same if I use own domain?

Price is the the same.