Hi Jo Pattyn.
I am not installing .NET 3.5 and as per workaround mentioned here https://support.microsoft.com/en-gb/help/3186435/sql-server-2016-database-mail-doesn-t-work-when-net-framework-3-5
I opted for Workaround 1 , created DatabaseMail.exe.config file and placed it in Binn folder , now when I double click DatabaseMail.exe it is not showing the .NET Framework 3.5 that error page .. but then mail is still not delivering. I have restarted the server also.
I am not sure what would be the easiest way to resolve this issue. My SQL server even running SP2 and as per these blog the issue is with only SP1.
This is my SQL Server version ..
Microsoft SQL Server 2016 (SP2-GDR) (KB4532097) - 13.0.5102.14 (X64) Dec 31 2019 22:39:35 Copyright (c) Microsoft Corporation Enterprise Edition: Core-based Licensing (64-bit) on Windows Server 2016 Standard 10.0 <X64> (Build 14393: ) (Hypervisor)