If you're sending to a mailing list, you may have received an error message containing the code "IRR". This means your account was temporarily blocked because we've detected the account has been attempting to send email to a large number of invalid addresses. Spammers quite often use "dirty" mailing lists with many invalid recipients. To ensure that your mail is delivered reliably, we have taken the step of blocking your email temporarily so that you can clean up the mailing list by removing invalid addresses.
If you receive this error, but are certain you did not send to a mailing list recently, then it's possible your account has been hacked and is being abused by a spammer. We highly recommend you contact your service or hosting provider, and change your password immediately. Furthermore, we recommend that you do a complete virus and malware scan to detect any harmful activity originating from your computer. After detection, potential viruses or malware must be treated and/or purged from your machine in order for MailChannels to resume normal email workflow.
If you run a mailing list, go through your bounces (non-delivery receipts), and purge any invalid recipient addresses from the list. Once you've removed your invalid recipients, our system will automatically detect that the invalid recipient counts are going down and the temporary block on the account will be removed.