System.NotSupportedException

Collection was of a fixed size.

        {

            if (targetUserId == fromUserId)

            {

                aliasIndicies?.Add(SearchConstants.OnlyMeIndex);

            }

Solution

I used Array.Empty<string>(); to create an empty array string. I then tried to later add an item to that array causing it to fail. I fixed this by using new List<string>(); instead.