sql server – DateTime conversion fails when the datetime has seconds


This seems to be most discussed, but I could not arrive at a solution yet. I have a date format and have to add a month to it (DATEADD should not be used as my date is string initially) and finally should convert it as date. 103 format converts but it does not give seconds.
Below is the code I tried

    Declare @time_info nvarchar(max)
Declare @format_time_info nvarchar(max)
Declare @time_info_final nvarchar(max)
Declare @time_detail datetime
SET @time_info='30/1/2020 20:34:16 6 300'

Select @format_time_info =  (Select REPLACE(@time_info,("https://dba.stackexchange.com/"+SUBSTRING( @time_info, 
CHARINDEX("https://dba.stackexchange.com/", @time_info) + 1, 
LEN(@time_info) - CHARINDEX("https://dba.stackexchange.com/", @time_info) - CHARINDEX("https://dba.stackexchange.com/", REVERSE(@time_info)))+"https://dba.stackexchange.com/"),
(CONCAT("https://dba.stackexchange.com/",(convert(varchar,(convert(int,(SUBSTRING( @time_info, 
CHARINDEX("https://dba.stackexchange.com/", @time_info) + 1, 
LEN(@time_info) - CHARINDEX("https://dba.stackexchange.com/", @time_info) - CHARINDEX("https://dba.stackexchange.com/", REVERSE(@time_info)))+1))))),"https://dba.stackexchange.com/")))) 

Select @time_info_final =(Select left(@format_time_info, charindex(' ', @format_time_info, charindex(' ', @format_time_info)+1)-1))
 Select @time_detail =  CONVERT(datetime, @time_info_final,103)-- Cast(@time_info_final as datetime)-- Convert(datetime,Cast(@time_info_final as datetime2),210) --
Print @time_info_final
 Print @time_detail

This throws the common exception