Types of Warnings
In the Formstack Sync mappings page, any mismatched fields or required fields that must be mapped in order to sync across systems, will give a warning.
The "mismatched field types" warning is only a potential warning. For example, a select field will sync to text field without an issue, but text field syncing to a select field must match the value of the select field option exactly. Read more here.
As shown above, a small warning icon will be present on every field that poses a potential syncing threat. When you open a field mapping with a mismatched field type, the different types will be displayed (see image below).
Required Fields - Any warning in red like the required field warning at the top of the page must be mapped or you'll run into errors trying to sync new records across your systems. Required fields must have a value for Formstack to be able to create a new record. If there is not a value coming from the other system Formstack will hit an error and the record will not sync. The solution to this issue is to create a default value for the field. This allows Formstack to create the record every time. Read more here.
Some field type warnings will cause errors. The most common of these are select fields and boolean fields. It is best practice to map all fields to a matching type. This is not always possible, in which case make sure that the field types will communicate with one another. Read more here.