Scan error type: other

[calebgk]

One of our guys found a document yesterday that explained Office365 is phasing this in. For now it only rejects a percentage of the connections. That's why it's intermittent. Kind of threw me at first.

Yes, they are rejecting a select amount of traffic on older protocols, and will gradually reject more, annoying people into upgrading their equipment/protocols.

New opt-in endpoint available for SMTP AUTH clients still needing legacy TLS - Microsoft Tech Community

From the link:

With this in mind, starting in September 2021, we will reject a small percentage of connections that use TLS1.0 for SMTP AUTH. Clients should retry as with any other temporary errors that can occur during submission. Over time we will increase the percentage of rejected connections, causing delays in sending that more and more customers should notice.

[lees]

We have also had a lot of problems with 4803 errors using office 365. What we found is to go to the Command Center > security settings > Network security. Uncheck SSL3.0/TLS1.0 and TLS1.1 in the client side and the server side settings, so that TLS1.2 is the only one that is selected. This has worked on several M3550's so far. We have not tried it on other models, but it is at least worth a try.

[PrintWhisperer]

Been dealing with this problem past week. All of our 00-series TA's that were previously using O365 are now incapable. I posted in the Connectivity thread about this. It seems MS deprecated TLS 1.0 and 1.1 last weekend. At least for plenty of my clients. Disable those protocols and SMTP starts working again on most machines, but all of the TA-xx00 and TA-xx50 machines won't work with O365, and need alternative SMTP.

You are correct on both counts. The '00' Series uses older network framework and only supports SMB 1.0 as well as not having TLS 1.2

This article presents many O365 configuration options which may be useful:

How to set up a multifunction device or application to send email using Microsoft 365 or Office 365 | Microsoft Docs