Snappy Nextcloud + calendar // Fatal error show

VPS: 1core/1G/40GB
Ubuntu 16.04
Snappy Nextcloud : v12.04 snap1
app: calendar, notes, task,

Got error message after I binding account for calendar ( CalDAV ):


Doctrine\DBAL\Exception\DriverException: An exception occurred while executing ‘INSERT INTO oc_calendarobjects_props (calendarid, objectid, name, parameter, value) VALUES(?, ?, ?, ?, ?)’ with params [“5”, 59, “DESCRIPTION”, null, “\xe6\xad\xa4\xe6\x97\xa5\xe4\xba\x94\xe5\xb8\x9d\xe6\x9c\x83\xe6\x96\xbc\xe5\x8d\x97\xe6\x96\xb9\xe4\xb8\x89\xe7\x82\x81\xe4\xb8\xb9\xe5\xa4\xa9\xe3\x80\x82\xe5\x87\xa1\xe4\xba\x94\xe8\x87\x98\xe4\xb9\x8b\xe6\x97\xa5\xef\xbc\x8c\xe4\xb9\x83\xe4\xba\x94\xe5\xb8\x9d\xe6\x94\x85\xe6\x9c\x83\xe4\xb9\x8b\xe6\x9c\x9f\xef\xbc\x8c\xe5\x85\xb6\xe6\x97\xa5\xe9\x85\x86\xe9\x83\xbd\xe5\x8c\x97\xe9\x99\xb0\xe5\xa4\xa9\xe5\xb8\x9d\xe8\x80\x83\xe6\xa0\xa1\xe9\xac\xbc\xe9\xad\x82\xef\xbc\x8c\xe6\x9f\xa5\xe7\x94\x9f\xe4\xba\xba\xe7\xa5\x96\xe8\x80\x83\xe5\x8f\x8a\xe8\xa6\x8b\xe4\xb8\x96\xe5\xad\x90\xe5\xad\xab\xe6\x89\x80\xe8\xa1\x8c\xe5\x96\x84\xe6\x83\xa1\xef\xbc\x8c\xe4\xbb\xa5\xe5\xae\x9a\xe7\xbd\xaa\xe7\xa6\x8f\xef\xbc\x8c\xe6\xad\xa4\xe6\x97\xa5\xe7\x9a\x86\xe7\xb4\xaf\xe7\x94\x9f\xe4\xba\xba\xef\xbc\x8c\xe5\xae\x9c\xe7\x95\xb6\xe9\x86\xae\xe8\xac\x9d\xef\xbc\x8c\xe9\xa0\x88\xe6\x86\x91\xe6\xb3\x95\xe5\x8a\x9b\xef\xbc\x8c\xe7\xa5\xad\xe7\xa5\x80\xe8\xbf\xbd\xe8\xb4\x96\xe5\xa1\x97\xe8\x8b\xa6\xef\xbc\x8c\xe4\xb8”]: SQLSTATE[HY000]: General error: 1366 Incorrect string value: ‘\xE4\xB8’ for column ‘value’ at row 1
/snap/nextcloud/4371/htdocs/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php - line 128: Doctrine\DBAL\Driver\AbstractMySQLDriver->convertException(‘An exception oc…’, Object(Doctrine\DBAL\Driver\PDOException))
/snap/nextcloud/4371/htdocs/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php - line 1015: Doctrine\DBAL\DBALException driverExceptionDuringQuery(Object(Doctrine\DBAL\Driver\PDOMySql\Driver), Object(Doctrine\DBAL\Driver\PDOException), ‘INSERT INTO `oc…’, Array)


Do I miss something config ?
Any advice on these? More thanks help.