SMTP server configuration - limits

On the server smtp.forpsi.com, the limits of number of sent emails per unit of time are given (250 emails per minute, 1000 emails per hour, 20000 emails per day), limit of number of recipients of one message (250), limit of number of messages in one session (250) and limit of number of emails bigger than 1 MB with recipients on Seznam (20 emails per minute).
 
  • Sending email limits set per unit of time
From one IP address or email account, you can send following maximum amount of messages:

250 messages per 1 minute
1000 messages per 1 hour
20000 messages  per day

When you exceed these limits, the email server returns an error message like this:
5.1.0 piWs1j0010jifNx01iWsdh policy violation
What to do if you get this error message: You have to send less emails per time unit, as seen above. If you need to send  more emails, contact us in a new ticket on portal support.forpsi.com.

SMTP server is configured as a shared server. This means that its services are used by ten thousands of customers. The purpose of the sending limits restriction is to prevent overloading of the SMTP server, which might be caused by sending masses of emails (business messages, newsletters, advertisement etc.). In this case, messages of other customers could be delayed, which is very unpleasant.
 
  • Limit of recipients for one message
Every message has a limit of maximum 250 recipients. When you send the message to more recipients, you get this error message:
5.1.0 piWs1j0010jifNx01iWsdh too many recipients
What to do if you get this error message: Split the mesage to more messages with less recipients. If you need to send  more emails, contact us in a new ticket on portal support.forpsi.com.
 
  • Limits for messages in one session
Every session has a limit of maximum 250 messages sent. After this, the session must be quit and a new one started. This restriction affects mostly programs which allow you to send multiple emails (SendMail and others) or use scripts. When you try to send more emails than the limit allows, you will get the following error message:
5.1.0 piWs1j0010jifNx01iWsdh too many messages per session, try again later
What to do if you get this error message: Set up the limit of messages sent per one session to 250. At the same time, you have to respect the time limits for sending emails as given above. If you need to send  more emails, contact us in a new ticket on portal support.forpsi.com.
 
  • Limits for messages sent to seznam.cz
It is possible to send at most 10 emails bigger than 1 MB to seznam.cz domains.

If more than 10 messages are sent from one email account in one minute to domain seznam.cz, email.cz, post.cz, stream.cz or firmy.cz, all other messages from this email accountin the one minute bigger than 1 MB with at least one recipient of the domain seznam.cz, email.cz, post.cz, stream.cz or firmy.cz are rejected with temporary error "Policy violation".

When you exceed these limits, the email server returns an error message like this:
5.1.0 piWs1j0010jifNx01iWsdh too many big messages to Seznam.cz
What to do if you get this error message: If you want to send more messages bigger than 1 MB, you have to send at most 20 such emails in one minute.
 
  • When you send bigger amounts of emails from one email or IP, no more than one half of the messages can be left in the mailserver's queue
The situation happens, for example, when you send more than 100 messages per hour from 1 IP  and more than 50 messages could not be delivered (stay in queue). All other messages you try to send from this IP will be rejected. The email client displays this error message with the email server's response:
5.1.0 piWs1j0010jifNx01iWsdh policy violation 
What to do if you get this error message: You should eliminate the reason why your emails are rejected by the recipient's server (full mailbox, incorrect address of recipient etc...).

Similar situation can occur when a customer (or customer's system) sends a lot of emails which cannot be delivered (e.g. because of exceeded recipient's mailbox quota,  invalid recipient address , etc.). In this case, the messages which cannot be delivered accumulate in the mailserver´s queue, which could grow excessively. For this reason, it is better not to accept messages exceeding a certain limit to prevent smtp server overloading.