SQL Server 2017

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-- working
SELECT CAST('2019-03-20T11:25:32.0342949' AS DATETIME2)

(No column name)

2019-03-20 11:25:32

-- also working
SELECT CAST('2019-03-20T11:25:32.0342949' AS DATE)

(No column name)

2019-03-20

-- not working
SELECT CAST('2019-03-20T11:25:32.0342949' AS DATETIME)
Msg 241 Level 16 State 1 Line 2
Conversion failed when converting date and/or time from character string.