Unless you are using TLSv1.2 or higher, you **will not** be able to talk to MS365. This was what they put into effect last month, and is a hard retirement.

You need to define your version to be TLSv1.2 for the client and/or server connectivity. Microsoft even made this announcement six months before they deprecated TLSv1 and TLSv1.1. Try setting your version to TLSv1.2 and see if it works now.

Thomas

On 10/26/21 11:33, Ben Bazian via stunnel-users wrote:

sslVersion = TLSv1