SQL 2016 Basic Availability Groups - worked until first restart

Hi,

I'am testing SQL 2016 Basic Availability Groups 

I created Test AG, everything shows OK but after restart, secondary server lost connection 

In AG dashboard I see error:

The availability group is not ready for automatic failover. The primary replica and a secondary replica are configured for automatic failover, however, the secondary replica is not ready for an automatic failover. Possibly the secondary replica is unavailable, or its data synchronization state is currently not in the SYNCHRONIZED synchronization state.

Maybe I something miss

I used scripts: 

---on test1 server

USE master
GO

CREATE AVAILABILITY GROUP TestAG
WITH
(
AUTOMATED_BACKUP_PREFERENCE = PRIMARY,
BASIC,
DB_FAILOVER = OFF,
DTC_SUPPORT = NONE
)
FOR DATABASE [testdb1]
REPLICA ON
'sql16-test1' WITH
(
ENDPOINT_URL = 'TCP://sql16-test1.mydomain.internal:5022', 
FAILOVER_MODE = AUTOMATIC, 
AVAILABILITY_MODE = SYNCHRONOUS_COMMIT, 
SECONDARY_ROLE
(
ALLOW_CONNECTIONS = NO
)
),
'sql16-test2' WITH
(
ENDPOINT_URL = 'TCP://sql16-test2.mydomain.internal:5022', 
FAILOVER_MODE = AUTOMATIC, 
AVAILABILITY_MODE = SYNCHRONOUS_COMMIT, 
SECONDARY_ROLE
(
ALLOW_CONNECTIONS = NO
)
)
GO

----- on Test2 server