NAS542 mail with STRATO account

As I know the mail server is using TLS, not SMTP port 25, and the NAS is using SMTP port 25 only, therefore, you need to use the account which default uses SMTP port 25.
Here is the information from strato mail for outbox and inbox server.
https://www.strato.com/faq/en_us/product/the-strato-email-server/