Assign: String was not recognized as a valid DateTime

Hello Arjun,
In this video I do a lot of stuff with String and DateTime:

0:35 Examples for Substring functions
4:10 IndexOf and LastIndexOf
5:00 SubString working together IndexOf and LastIndexOf
6:45 Split string by character
8:50 Split string by string
12:00 Lower Case and Upper Case
12:45 Trim
15:05 Compare strings in multiple ways
19:05 Resume of all the String function part
20:05 DateTime to string in multiple ways
23:00 AddDays get DayofWeek
25:40 Convert from String to DateTime
26:20 Compare DateTime

Thanks,
Cristian Negulescu