Why did a website reject my temp address?

The site checked your address's domain against a blocklist of known disposable-email providers — and the domain was on it. The address itself is perfectly valid; it just isn't wanted. Rejections feel arbitrary because each site subscribes to different lists, updated at different times: the same temp address may pass on one site and fail on the next.

Why sites do this

• Trial abuse — “one free trial per person” is unenforceable when anyone can mint a hundred addresses.
• Ban evasion — banned users shouldn't return with a fresh inbox.
• Spam and fake engagement — communities and referral programs get flooded through disposable sign-ups.
• Deliverability discipline — services that will email you an invoice in eight months want an inbox that still exists.

What you can realistically do

1. Try another domain — temp-mail services run several receiving domains and blocklists don't always cover all of them. Tap the domain button and generate a new address. Worth one attempt, not ten.
2. Skip custom names — blocklists check the domain, not the name, so renaming won't help.
3. Take the hint — if the site insists on a durable address, it probably plans to send you invoices, licenses or recovery mail later. Use your real inbox there.

There's no guaranteed bypass, and you should be wary of any temp-mail site claiming one. The full picture is in Why Some Websites Block Temporary Email Addresses.