Rebex Secure Mail
SMTP, IMAP, EWS, POP3, S/MIME .NET library
Download 30-day free trial Buy from $299
Rebex Secure Mail for .NET (30 day trial)
for .NET 2.0-4.8, .NET Core/.NET Standard, Mono, Xamarin.iOS, Xamarin.Android
Version 2019 R3.1 (Latest version)
Download Windows installer (trial)
Easiest and most popular option
NuGet
1) Add NuGet reference 2) Unlock for a trial period using trial key
Rebex Secure Mail (Legacy) for .NET Compact Framework (30 day trial)
for .NET Compact Framework 3.5-3.9
Version 2019 R3.1 (Latest version)
Download Windows installer (trial)
Easiest and most popular option