topic Re: SMTP error 452 in Email

SMTP error 452 (too many recipients in the last hour)

B0n3s — Sun, 14 Sep 2025 13:24:14 GMT

Anyone getting:

SMTP error (452): Failed to add recipient
recipient rejected - too many in the last hour

Not using VPN. Tried via PlusNet IP
Sent very few mails today and never more than a couple of recipients in each message.
Seems to be any address I try. Tried 4 different ones.

Moderator's note:
Title amended to improve understandability

Re: SMTP error 452

B0n3s — Tue, 19 Aug 2025 14:15:19 GMT

LOL.
As soon as I post, it's been "fixed"

Re: SMTP error 452

d-dixon — Tue, 19 Aug 2025 16:24:20 GMT

Not fixed here. I see the same (Force9 email, sending from my Plusnet line) - choice and number of recipients makes no difference. Bizarrely, the time does - lots of failures if sent at xx:53, xx:57, xx:59, but then everything starts working again a minute later at xx:00. So I now have to remember to only send emails just after the hour...

Re: SMTP error 452

Townman — Tue, 19 Aug 2025 16:45:59 GMT

If you are sending a lot of emails, you will see this behaviour. There are rate limits per hour and they are different depending on where you are sending from.

Re: SMTP error 452

d-dixon — Tue, 19 Aug 2025 17:15:23 GMT

Thanks - I've sent 3 emails today, each to 1 or a small number of recipients, so that doesn't sound too excessive to me. Is my quota getting bundled up with a larger user base?

David

Re: SMTP error 452

Townman — Tue, 19 Aug 2025 17:33:16 GMT

Hi David,

Are you using a VPN? If yes then the the sum of submissions from all users will be treated a single source.

There are arguments for not using a VPN except for where there is a business need to connect securely to a remote network, as for instance connecting into a corporate network remotely, as though you were on the premises.

There is very little legitimate reason for using a VPN to pretend you are elsewhere, more often than not, their use creates more real problems than they solve.

Re: SMTP error 452

d-dixon — Tue, 19 Aug 2025 20:37:20 GMT

@Townman wrote:

Hi David,

Are you using a VPN?

No VPN - just my default, fixed IP address,

David

Re: SMTP error 452

mavison — Wed, 20 Aug 2025 10:11:47 GMT

I have also had a few of these errors this month: 452 <xxx@xxx> recipient rejected - too many recipient in last hour.

In both cases the email was to a single recipient, and was the first sent for at least an hour.

I am also a Force9 user, with static IP, no VPN, sending to relay.force9.net, port 465 with SSL/TLS

Re: SMTP error 452

B0n3s — Wed, 20 Aug 2025 13:42:01 GMT

Ah, not fixed after all. Returned again today. 😐

Re: SMTP error 452

B0n3s — Wed, 20 Aug 2025 13:43:54 GMT

Curiously, around the same time as yesterday. PlusNet load issue maybe?

Re: SMTP error 452

offscotland — Fri, 22 Aug 2025 20:04:17 GMT

I can confirm the time issue of this error.

I tried sending a message every minute from 20:54 and it was bounced each time with the 452 error. As soon as the clock clicked to 21:00 the exact same message sent without a problem....

Re: SMTP error 452

Townman — Fri, 22 Aug 2025 20:13:31 GMT

What is the A.B.C.x IP address of those users experiencing the issue?

Re: SMTP error 452

offscotland — Fri, 22 Aug 2025 20:22:42 GMT

Tell me how to find that and I'll let you know. I am using Webmail with Windows 7 Professional and have done for many years.

Re: SMTP error 452

d-dixon — Fri, 22 Aug 2025 20:24:08 GMT

@Townman wrote:

What is the A.B.C.x IP address of those users experiencing the issue?

For me: 212.56.120.x

Re: SMTP error 452

offscotland — Fri, 22 Aug 2025 20:36:22 GMT

Ethernet adapter Local Area Connection:

   Connection-specific DNS Suffix . : lan
   Link-local IPv6 Address . . . . . : fe80::9c47:f53a:12c1:a900%10
   IPv4 Address. . . . . . . . . . . : 192.168.1.67
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.1.254

Re: SMTP error 452

d-dixon — Fri, 22 Aug 2025 20:47:16 GMT

@offscotland wrote:

Tell me how to find that and I'll let you know.

https://whatismyipaddress.com/

Re: SMTP error 452

Townman — Fri, 22 Aug 2025 20:50:07 GMT

That’s the LAN address - it is the WAN address which is relevant - use what’s my IP address

Re: SMTP error 452

mavison — Fri, 22 Aug 2025 21:09:30 GMT

My WAN address is 84.92.10.xx (static)

Re: SMTP error 452

Townman — Fri, 22 Aug 2025 21:37:33 GMT

Oh!

That points away from a suspect profile.

Re: SMTP error 452

offscotland — Sat, 23 Aug 2025 07:44:26 GMT

See attached