On the contact record in ConnectWise you will find standard address type fields such as Street, City, State, etc. These fields, while may appear to live on the Contact, are actually pulling in values for these Address fields from the related Site that the Contact is tied to within ConnectWise. Because of this, these fields are Read-Only fields and you can not write into them from another systems contact record.
In addition to the above Read-Only nature of these fields, they will only display a value if the Contact is associated with the Main Site. If they are related to any of the other Sites in ConnectWise, the address values will not be visible since at this time Formstack Sync's ConnectWise Connector does not pull in data from all related Sites.