Here is info about our technical development environment :

• .NET 6
• C# 10
• Hasura GraphQL v2.6.2-pro.1
• Micrsoft SQL server 2019
• Visual Studio 2022
• "GraphQL" version="7.3.1" Proxy
• "GraphQL.Client" version="5.1.1" Proxy
• "GraphQL.Client.Serializer.Newtonsoft" version="5.1.1" Proxy

I have application code that

1. Converts integer-based Unix timestamp into a C# DateTimeOffset
2. I convert said C# DateTimeOffset to a C# DateTime
3. The C# DateTime value is converted into a string-based DateTime format

Here is the code in question:

_DateCreated = DateTimeOffset
    .FromUnixTimeMilliseconds(emailEvent.TimeStamp)
    .DateTime
    .ToString("dd-MMM-yyyy hh:mm:ss tt");

Unfortunately, when I run the aforementioned code, I get the following error:

{"Errors (1)\r\n1: Data exception. Invalid datetime format. [Microsoft][ODBC Driver 18 for SQL Server][SQL Server] The conversion of a nvarchar data type to a datetime data type resulted in an out-of-range value.\r\n"}

I searched the internet, and came across the this posting:

https://stackoverflow.com/a/2307624/1338998

In the aforementioned posting, one of the commentors states the following:
The safest possible "date time" format from .net to sql I have used to date is "yyyy-MM-dd HH:mm:ss.fff". PK :-)

Therefore, I changed my code in such way that the datetime’s string format would be different like in the following refactored code:

_DateCreated = DateTimeOffset
    .FromUnixTimeMilliseconds(emailEvent.TimeStamp)
    .DateTime
    .ToString("yyyy-MM-dd HH:mm:ss.fff");

Essentially, I changed the Datetime formatting of string from:

…………..DateTime.ToString("dd-MMM-yyyy hh:mm:ss tt")

To

………………….DateTime.ToString("yyyy-MM-dd HH:mm:ss.fff"),

I no longer received the error.
However, my concern is whether the error throwing up really depends on the region date and time setting of the server that hosts my application.

To elaborate, my current server that host the application has the following region date and time settings:

Therefore, if someone changes said date and time format settings on the host server then the error might show up again regardless of what kind of C# datetime formatting that I use in my application code.

Therefore, I’m wondering if my C# datetime formatting would be in vain if the host server’s date and time format settings are changed.

How can I make changes to my C# datetime formatting code in such a way that it is more robust/fault-tolerant so that it will works regardless of the date and time format settings on the host server?