Emails may be not received by your clients for different reasons. One of the most popular reasons is that an email address provided by your client doesn't exist or is invalid. Such emails are considered errors.
How to avoid getting the Error status
For example, you have created an email campaign. In campaign statistics, you see that some emails have the Has errors status. As it affects your daily limit, you need to get a list of the recipients' email addresses with errors and add them to exclusions when creating your next email campaign.
Click on the number of errors in the campaign statistics section.
Click the cogwheel button > Export data to get a list of recipients with the Has errors status.
Open the file and copy the list of email addresses.
After that, you can use one of these two options to prevent your email campaigns from being sent again to these email addresses.
Add email addresses to the Black List
Create a special segment
No matter which option you've chosen, messages won't be sent to email addresses specified in the exclusions list or black list, and you won't get errors from these recipients for a second time.