The Windows Server Failover Clustering (WSFC) resource control API returned error code 19 What is root cause of this error. I couldn't find any related information.
There are two nodes on Availability Group and if you reboot second node, database wont up.
Here are the details of that error code (19):

ERROR_WRITE_PROTECT
19 (0x13)
The media is write protected.

You need to consult the cluster log (use Get-ClusterLog to get that) for additional details about what writes failed within the cluster operation being performed.  Check that out and update your question with any errors you see.
That being said, combined with this symptom:

...if you reboot second node, database wont up.

You might be experiencing disk problems.  Check the Windows system event log and SQL Server error log for messages related to failed writes or corruption.