Error: No address associated with hostname

This error implies that your device does not have access to your Microsoft Exchange Server. In some cases this could mean that the device does not have an internet connection, and in other cases the provided address is incorrect.

This refers to the address of your Exchange server. Typically, it would be something like owa.domain.com or mail.company.com. For Microsoft 365 users, this value is set automatically to mail.office365.com as long as you choose Microsoft 365 from the server options.