Connection closed by server.
Failed to read beginning of SSL/TLS record.
Failed to read incoming handshake messages. (1)
Client handshake failed.
Failed to establish TLS connection.
Why is this happening
When sending an email via office 365 from sage 100 or older, it uses TLS 1.0 or 1.1, which is the encryption used for connection between Sage 100 and Office 365. Microsoft has recently changed the encryption to default 1.2, and are slowly deprecating the use of the less secure TLS 1.0 and TLS 1.1.
Sage 100 2018 and older versions do not support TLS 1.2.
Workaround
There are three workarounds
- Consider upgrading to a current version of Sage 100 . This is as per the solution ID: 106485 from sage
- Temporarily use an SMTP service like smtp2go.com. Please use this at your own risk. Once setup, you would reconfigure Sage 100 to use the SMTP2Go configuration.
- You can enable Legacy protocols on Office 365 tenant until the Sage is upgraded using Powershell via the Online Exchange Management, by doing the following:
- Run the following Powershell command: Set-TransportConfig -AllowLegacyTLSClients $True
- If smtp server smtp.office365.com does not work try using legacy-smtp.office365.com

Solutions 2 and 3 are provided as courtesy. gotomyerp is not responsible for any interruption to your mail service due to any misconfiguration on your Exchange tenant. If you are unsure how to do this properly, please consult with an IT Professional to assist.
More information on workaround is listed here