How to Check a List of ziggo.nl Email Addresses (Bulk, Free)
A Dutch list with ziggo.nl rows can be cleaned in one pass: the bulk Ziggo email checker flags syntax, duplicates and dead domains for every row and asks Ziggo's server about the first 10. Sign in with Google for the free checks on the rest.
Ziggo rejected made-up addresses with 550 MXIN501 mailbox … unknown on 12 October and 8 November 2026, so a missing ziggo.nl mailbox comes back invalid.
Reading the Ziggo reply
On 8 November 2026 ziggo.nl published two MX hosts, mxin5.ziggo.nl and mxin10.ziggo.nl. On 12 October they answered a made-up address at RCPT TO with 550 MXIN501 mailbox … unknown, and a fresh one got the same rejection on 8 November. MXIN501 is Ziggo's own code; the 550 and the words "mailbox unknown" carry the verdict.
Why old rows stop working
Ziggo's mail help page (Dutch) says a customer can't keep a Ziggo address after cancelling or switching provider; access continues for six months after cancellation. A ziggo.nl address that is a year or two old therefore often belongs to someone who has moved on.
The by-hand way
- Filter the sheet to ziggo.nl.
- Remove repeats and typos.
- Test addresses one at a time with the Ziggo email checker.
In the tool
Paste the list, read the flags for typo domains, duplicates, +tag repeats and dead domains, download the clean list, and let the first 10 reach Ziggo for a live answer. For the other big Dutch provider, there is a bulk KPN checker.
What this check cannot do
- Ziggo doesn't publish how its servers answer mailbox checks; the handling is from our own checks, which can change.
- Older Ziggo-era domains such as upcmail.nl and home.nl aren't matched as Ziggo rows.
- A +tag repeat is marked as possibly the same inbox, not merged.
- Valid means the mailbox exists today, not that anyone reads it.
Next: the whole list
The verify page on simpleverifier.com takes any list size: the first 100 checks are free with a Google sign-in, no card.
Try it now
Paste your list into the bulk Ziggo email checker.
Common questions
Can you check ziggo.nl addresses in bulk?
Yes. Ziggo's server rejected made-up addresses with 550 MXIN501 mailbox unknown on 12 October and 8 November 2026, so a missing mailbox comes back invalid. The first 10 are asked live; sign in with Google for the rest.
What does MXIN501 mean?
It is Ziggo's own code. The 550 and the words mailbox unknown in the same reply carry the verdict: the mailbox doesn't exist.
Can customers keep a Ziggo address after cancelling?
Ziggo's help page says no: access to the mail continues for six months after cancellation or switching provider.
Are kpnmail.nl and upcmail.nl Ziggo rows?
No. Only ziggo.nl counts; other domains are checked as normal addresses and marked as another provider.
Will the owners know I checked?
No. The check ends after the mail server answers about the mailbox, before any message content is sent.
Check your list before you send
Real mailbox checks over SMTP, and nothing is sent to the address. Sign in with Google and your first 100 email checks are free, no card. Plans for bigger lists are on the pricing page.