Probably, you are committing the cardinal sin in SQL access, and concatenating striungs to form an SQL command:
Dim cmdString As String = "INSERT INTO MyTable (dateColumnName) VALUES ('" & myDateTimeValue.ToString + "')"
Don't - that is always prone to errors, and if you are habitually using it, you leave your database wide open to an SQL injection attack which can easily damage or destroy your database.
Use a parameterised query instead, and the problem will disappear:
Using con As New SqlConnection(strConnect)
con.Open()
Using com As New SqlCommand("INSERT INTO myTable (dateColumnName) VALUES (@DT)", con)
com.Parameters.AddWithValue("@DT", myDateTimeValue)
com.ExecuteNonQuery()
End Using
End Using