After update to 15.19, I found my Forerunner 955 Solar was unable to sync with Garmin Express.
An error occurs: "There was an error syncing with Garmin Connect"
already update to the latest version of Garmin Express:
BTW, I asked one of my friends who also has Forerunner 955 Solar and updated to 15.19 recently, he had the same syncing problem after updating.