"Risky" isn't one thing. Kickbox's risky label covers accept-all, disposable and role addresses, per its docs read on 24 September 2026. Instantly labels a lead risky/unknown and says that's often because the domain is catch-all. ZapBounce keeps them apart: the result is valid, invalid, catch_all or unknown, and role and disposable are separate flags.
A catch-all row means the domain accepts every address, so nobody can confirm the mailbox. About 28% of addresses in a 10,000-email B2B benchmark sat on such domains, so dropping them all can cut more than a quarter of your list. Send them after your valid rows in a small batch, watch the bounces, and stop if they pass 2%, the level Amazon SES recommends.
An unknown row is different, because the server never answered. Greylisting, throttling, a blocked probe or a timeout all end there, and several of those clear on a second try. Re-check unknown rows a day or two later. Send the ones that come back valid, and drop any that stay unknown unless your own data shows a recent reply.
Treat the flags on their own terms. Disposable addresses rarely belong on a list you mail. Role addresses like info@ can work for a customer notice and fail as a cold pitch; our page on role accounts walks through the call.
Keep risky rows out of your first wave, whatever you decide. Bounces land on the domain you send from, and Amazon SES reviews an account at 5% and may pause it at 10%. ZapBounce bills catch_all once and never bills unknown, so a re-check costs a credit only when it gets a real answer. Run the pass through bulk verification.
Related questions
What does risky mean in email verification?
Risky is a vendor label that usually covers catch-all domains and sometimes disposable or role addresses. Kickbox's risky label includes accept-all, disposable and role. Check your vendor's docs, because the mix changes how you should send.
Is it safe to send to unknown emails?
Not before a re-check. An unknown means the server gave no answer, often from greylisting or throttling that clears on a later try. Re-verify first and send only the rows that come back valid.
When should I stop a risky email batch?
Stop a risky batch once bounces pass 2%. Amazon SES recommends staying under that line, and its enforcement FAQ, read on 24 September 2026, puts accounts under review at 5%.
Do risky emails cost a credit to verify?
At ZapBounce a catch_all result costs one credit, the same as valid or invalid. Unknown results never cost anything, and neither do duplicates.