SQL Mirror stuck Synchronizing after failover

I recently failed over my primary SQL database to it’s copy on the mirror SQL server. This part worked well, however when I went to fail back the database displayed “Primary / Synchronizing …” In this state it’s impossible to failover.

When looking into this further I checked the Mirror Monitoring tool in SQL and saw that there were 0KB of logs left to synchronize.

In order to repair the issue, I had a developer commit some minor changes to the database. This queued a log to move to the mirrored server and the status of the database changed back to “Synchronized”. I was then able to failover to my primary database server.