Forum Discussion

Philippe Schnyder's avatar
Philippe Schnyder
Copper Contributor
May 10, 2018

550 5.7.501 Service unavailable. Banned Sender. - no help from Support

Hi   I've sent out less than 400 emails using SMTP today (while keeping in mind https://technet.microsoft.com/en-us/library/exchange-online-limits.aspx#Receiving%20and%20sending%20limits, so 30 mai...
exchange
office 365
Philippe Schnyder's avatar
Philippe Schnyder
Copper Contributor
May 10, 2018

Good point: But the program needs another 20-30 s to send the emails so it's actually much more (at least 80s per 30 mails)

Update: I've added a log which clearly shows I never as near the 30 mails per 60s limit:

Update2: Didn't work, so I put it on PasteBin: https://pastebin.com/EVRH4q1g

Steven Collier's avatar
Steven Collier
MVP
May 10, 2018

But is that additional equally spread between each message, Microsoft will only see the SMTP connections, maybe your app takes 30seconds to get ready before it starts sending the first SMTP.

 

Absolutely my personal opinion, but I would always aim for 50% or any threshold value and double any time estimate.

  • Philippe Schnyder's avatar
    Philippe Schnyder
    Copper Contributor
    May 10, 2018

    Thank you for your help:
    Please let's split up this discussion in two things

    a) Currently my real issues are that:
    1. I can't send mails using MAPI / Outlook / OWA
    2. Internal messages that are automatically forwarded (by a forward setup by the user) are not forwarded if they are from me (because I'm banned).
    3. I as an Admin can't resolve this.

    b) Regarding the mass mailing:
    1. I'd like to mention that this worked just fine the last years.
    2. I clearly never sent more than 30 mails per 60 seconds (or within a specific minute)
    Actually per SMTP connection 30 mails are sent. Then the connection is closed and the app sleeps for 62 seconds. Then a new SMTP connection is established.
    Never the less I can change the settings as you suggested but I wonder why those limit are posted if the recommendation in the end is to do half of it?

    Thank you

     

    Update: Also why would I be banned and not temporarily blocked when going over the 30 mails per minute? It seems to be a rather harsh approach!

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