Forum Discussion
MarcVHB
Feb 19, 2020Copper Contributor
Can't send SMTP mail after setting Default Security in Office 365
After I activated the 'Default Security' in Office 365, the multifunctionals can't scan-to-mail . I get error SmtpCmdResp: 535 5.7.3 Authentication unsuccessful [LO2P265CA0457.GBRP265.PROD.OUTLOOK...
- Dec 01, 2020
LusoAdmin Hey there. I'll put the solution here because as far as I can tell, everyone should also have that problem now. It took 1 week with the Microsoft support to finally find the solution. Just like I thought, because now the default security is enabled when you create a new tenant, even if you disable it, smtp somehow stays disabled and that overrides the settings in your admin panel.
All you have to do is enable it in Powershell. To connect with Powershell, first you have to execute this:
Connect-MsolService
Import-Module ExchangeOnlineManagement
Connect-ExchangeOnlineThen you enter your admin credentials. After that, you can check the "smtp disabled" flag, it should be set to "true":
Get-TransportConfig | Format-List SmtpClientAuthenticationDisabled
To enable smtp and get things working again, you enter this command:
Set-TransportConfig -SmtpClientAuthenticationDisabled $false
Worked for all my tenants. I hope this helps you too!
VasilMichev
Feb 19, 2020MVP
Well you might have bothered to read the documentation on Security defaults first to avoid such issues 🙂 Among other things, they block basic auth for SMTP, which I suppose is what your devices use. You can either disable Security defaults, create a similar CA policy with exceptions added for the devices, or use some smart host/relay to route those messages.
HSTico
Jul 08, 2021Copper Contributor
How can I create such an Conditional Access Policy for enabling SMTP again?