Errors with your email client (e.g., Microsoft Outlook, Apple Mail, Mozilla Thunderbird)


Check the outgoing server (SMTP) name: it must be authsmtp.securemail.pro or authsmtp.yourcompany.co.uk (see Standard Configuration Parameters guide or SSL Standard Configuration Parameters guide).
Important: if you read a different server name, you are not using the correct email service.


Also, verify that the outgoing server requires authentication and uses the specific credentials for the SMTP service provided to you with the Service Activation Letter (SAL).


No error message


If the message is indeed sent but does not reach its destination, you need to check with the recipient the reason for non-receipt.


Error: MAX RCPT TO DAILY LIMIT


This error indicates that you have reached the daily sending limit allowed according to your plan (the basic one allows 1,000 messages per day, considering all your email accounts).

You can purchase additional sending packages, use webmail (e.g. webmail.yourcompany.co.uk), or wait until midnight when the sending counter will reset.


If you do know you have not exceeded this limit, you might be a victim of malware or password theft.

In this case, run a full antivirus/antimalware scan on all workstations where the email accounts are set up and then request a password change for your outgoing mail service (SMTP).


Error: SENDER REJECTED


The inability to send messages with the error "sender rejected" lasts for 4 hours and occurs when temporary errors are generated for 66% of the emails sent from the email account in the last hour (e.g. more than 250 sendings per minute or too many wrong recipients).


Verify if such emails were sent by you or the users accessing the email account; if not, perform a full antivirus/antimalware scan on all devices accessing the mailbox and then change the access password via webmail (e.g. webmail.yourcompany.co.uk), as it may have been identified by third parties for sending spam, causing temporary errors and thus the block.


Also, being blacklisted by the IP address of the connection used could result in a high number of errors following the emails; in this case, it is advisable to contact your network provider (e.g. BT, Virgin Media, Vodafone) to request the delisting of the IP or the assignment of a clean IP. Often the IP address of your connection is not static; restarting your router could result in a new one.



Performing anti-malware security checks


Some recommended tools to scan your devices:


Checking if your IP address is on a blacklist


  1. Search "my IP address" on Google or click on https://www.myipaddress.com
  2. The number you see (e.g., 78.123.13.200) is the address assigned to you by your network provider (e.g. BT, Virgin Media, Vodafone)
  3. Click on https://mxtoolbox.com/blacklists.aspx or https://talosintelligence.com/reputation_center/lookup and enter it in the search box to check its reputation and its presence on international blacklists.