If you have configured GMS Cloud using a trial domain – such as mycompany.gms-cloud.com and you have added your full company domain name later (e.g. mycompany.com), you will likely wish to update your settings so that your emails you send now use the correct email address for your company domain.
For webspace or webmail, simply login using your email address with the correct domain name – and your emails will be sent correctly.
For Outlook or another client, repeat the steps in the article for setting up your client, but modify the email address to be your correct company branded domain.