Why wasn't a specific contact synced?

This can have a variety of reasons. You can find the exact reason in the sync log (Dashboard -> "Actions" column -> Download sync log).

In general, the following reasons are conceivable:

• The contact does not meet the minimum requirements of sync.blue®:
  • E-mail address or first name and last name ("People")
  • Company name ("Companies")  
• The target app has special requirements so that a contact can be saved at all (e.g. Placetel: a contact must have at least one phone number). All known requirements can be read here.
• The contact in the source is of a contact type (e.g. "company") that Sync target not supported (see Compatibility list)   
• The contact has fields with invalid or unusually formatted fields (date of birth, e-mail address,...) and was therefore ignored.
• The contact exists several times in the source (identical first and last name or email address) and is therefore deliberately only synchronized once with the target.

If the reason is still unclear, please email us a screenshot of the source contact for more in-depth analysis.