This is a domain-wide setting where all emails on this domain will be considered as accept all (unverifiable) which is also called a "catch-all". There is no method to determine if this email is valid or invalid.
An Accept All address is usually used in small businesses to guarantee an organisation gets all the emails that sent to them, regardless of grammatical mistakes.
Most often these are valid emails. But in some cases, organisations can use this setting as a security method to avoid unsolicited emails.
SAFE – if you have a dedicated email server with your own IPs, catch-all emails may be safe for sending dependent on the overall health of your list.
DON’T SEND – if you use a third-party email provider that requires a bounce rate below 4%, these emails are not safe for sending.
For you to know more:
The percentage of accept alls is directly correlated to the amount of "Invalid" emails within a set of data. Therefore the higher the invalid rate, the more likely the accept alls are to bounce. If you have a fairly clean list, the accept alls have a better chance of being "valid" results.
Usually, accept alls tend to bounce at half the rate of your original invalid percentage. So for example, if you had 10% invalids within your list, it is possible up to 5% of your accept alls will still bounce. This is very important to be aware of when it comes to sending to accept alls.
If you know for sure where your data came from, you tend to have fewer problems with bounces rather than data that you are unsure of or that you purchased.
Sending in small groups (at your choice) and monitoring which ones bounce back (these will be emails you will want to remove of your data) can help you begin extracting invalid emails from your list. Some ESP's will provide a higher amount of accept alls to be sent at once, but we would recommend contacting the sending platform of your choice to gather any additional information. You may also try using another email account to do some catch-all sending to see which ones bounce back (these will be invalid, and the emails that don't bounce most likely made it through to their intended destination) this way you will not hurt your sending status with your primary email account or sending platform.