web
You’re offline. This is a read only version of the page.
close
Skip to main content

Announcements

No record found.

News and Announcements icon
Community site session details

Community site session details

Session Id :
Small and medium business | Business Central, N...
Suggested Answer

Failed Emails in Outbox

(1) ShareShare
ReportReport
Posted on by 292
Everyday we have failed emails within BC with either of the following failed messages:
Could not send the email.

4.3.2 Concurrent connections limit exceeded. Visit https://aka.ms/concurrent_sending for more information. [Hostname=ME3PR01MB7080.ausprd01.prod.outlook.com]
Or: 
Could not authenticate on the SMTP server.

421: 4.3.2 Service not active [SY5PR01CA0037.ausprd01.prod.outlook.com 2024-10-08T20:25:34.383Z 08DCE7B7BEC171CA]
 
The emails are either remittance advices we are sending to vendors which are sent once a week or they are Notification overviews which are sent to our approvers daily.
We have reset the Rate Limit per minute on our Email account to 20 as I am aware there is a throttling limit for the SMTP Authentication of 30 messages per minute and a recipient rate limit of 10,000 recipients per day.  We are definitely not reaching 10,000 recipients per day. 
 
Is anyone currently or has anyone experienced this issue? I have reached out to our IT department and our partner who are unable to provide any solutions.  We have staggered the time we send remittances from our four companies so they are not all going at the same time and each week I clear the outbox of failed emails.
 
Any help, idea or suggestions anyone might have in relation to this would be appreciated. 
 
 
I have the same question (0)
  • Suggested answer
    YUN ZHU Profile Picture
    99,978 Super User 2026 Season 1 on at
    I think this is not a BC problem, but a mail server problem. You can try a private mailbox, such as Outlook. If the problem disappears, you still need to ask your IT department to assist in the investigation.
     
    Hope this can give you some hints.
    Thanks.
    ZHU
  • Sacha E Profile Picture
    292 on at
    Thanks Zhu. This was also what was I thinking but I was hoping someone else might have experienced the same or a similar issue and be able to offer some insight into how they resolved it. We are using Outlook.

Under review

Thank you for your reply! To ensure a great experience for everyone, your content is awaiting approval by our Community Managers. Please check back later.

Helpful resources

Quick Links

Introducing the 2026 Season 1 community Super Users

Congratulations to our 2026 Super Stars!

Meet the Microsoft Dynamics 365 Contact Center Champions

We are thrilled to have these Champions in our Community!

Congratulations to the March Top 10 Community Leaders

These are the community rock stars!

Leaderboard > Small and medium business | Business Central, NAV, RMS

#1
OussamaSabbouh Profile Picture

OussamaSabbouh 1,796 Super User 2026 Season 1

#2
YUN ZHU Profile Picture

YUN ZHU 965 Super User 2026 Season 1

#3
Teagen Boll Profile Picture

Teagen Boll 664 Super User 2026 Season 1

Last 30 days Overall leaderboard

Featured topics

Product updates

Dynamics 365 release plans