Non-nullable property 'UserId' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'UrlTemplate' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'EmailAddress' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Converting null literal or possible null value to non-nullable type.

Possible null reference return.

Non-nullable property 'Subject' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'PerformedBy' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Message' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Nullability of type of parameter 'value' doesn't match overridden member (possibly because of nullability attributes).