Quick answer
How do I move email to a new provider without losing mail?
Lower the TTL of your MX records to 300 to 600 seconds 24 to 48 hours ahead, import the old archive into the new mailbox, change the MX records last, and keep the old account until new mail has arrived. Postelva hosts the DNS, so the switch is one edit to two or more records.
How many records change when you move
| New provider | MX | Verification TXT | SPF | DKIM | DMARC | Records in total |
|---|---|---|---|---|---|---|
| Proton Mail | 2 | 1 | 1 include | 3 CNAME | 1 | 8 |
| Mailbox.org | 4 | 1 | 1 include | 4 CNAME | 1 | 11 |
| Fastmail | 2 | Not required for MX-only setup | 1 include | 3 CNAME | Not read (not verified) | 6, without DMARC |
Five steps in the right order
Lower the TTL
At least 24 to 48 hours before the move, set the TTL of the MX records to 300 to 600 seconds. A change spreads in about the old TTL, so a short value before the change makes the change fast.
Prepare the new mailbox
Add your domain at the new provider, create the addresses and aliases, and copy the verification record it shows. Do not touch the MX records yet.
Copy the old mail
Import the archive with the new provider's IMAP import tool while the old account still receives mail. Forwarding alone moves only new mail.
Switch the MX records
Replace the old MX records with the new ones, add the new SPF include to the existing SPF record and add the DKIM records. Keep the old server accepting mail until the old TTL has passed.
Confirm, then clean up
Send yourself a test from two outside accounts, check the headers, keep the old account for a while, then raise the TTL again and delete the old records.
Why does the TTL decide whether mail is lost?
The TTL is the number of seconds a resolver may keep an answer, so it sets how long senders keep using your old MX records. If the old TTL is 86400 seconds, a sender that looked you up one minute before the change keeps delivering to the old server for up to a day. With a TTL of 300 to 600 seconds the window is five to ten minutes.
The rule from deliverability guides is to lower the TTL 24 to 48 hours before the move, so that every cache already holds the short value on the day, and to raise it again afterwards. A typical MX change then settles in 1 to 4 hours, and can take 24 to 48 hours in the worst case. This is vendor guidance, not a standard. Empty answers are cached too, with the TTL of the zone's SOA record (RFC 2308), so a record you create late can stay invisible for a while at some resolvers.
How do I copy my old mail before the switch?
Import the old archive over IMAP before you change a single MX record. Proton Mail, for example, documents a switch from Gmail with an import tool, and the advice of provider migration guides converges on the same order: import first, change MX only when the destination is ready, keep the old account until you confirmed that everything arrived.
Two habits prevent most losses. First, keep the old mailbox receiving mail while the import runs, because mail that arrives during the copy will be in the old account only. Second, run a second, short import after the MX switch to pick up the messages that landed at the old server during propagation. For the order of work when your address changes provider but not name, read how to keep your email address when you change provider.
How do I switch the MX records safely?
Remove the old MX records or give the new ones the lowest priority number, and never leave two providers mixed. Fastmail and Proton Mail both say this in their help pages: with old and new records side by side, mail is delivered to either server unpredictably. An MX record names a mail server and a priority; senders try the lowest number first. The concept is explained in what an MX record is.
At Postelva, the zone is edited in the client area, and one-click DNS templates for Proton Mail, Fastmail, Zoho Mail, Google Workspace and Microsoft 365, plus an SPF + DMARC template and a "no email" template for a domain that sends nothing. A template replaces the MX, SPF and DKIM records for the provider in one action. For Tuta, Mailbox.org, iCloud+ and Migadu you type the MX, TXT and CNAME records in the DNS editor, using the values shown in the provider's own screen.
What happens to SPF and DKIM during a move?
A domain may publish only one SPF record, so add the new provider's include to the existing record instead of creating a second one. Proton Mail, Mailbox.org and Mailfence all give the same instruction. Keep the old include in the record until you have stopped sending from the old provider, then remove it: the SPF check allows at most 10 DNS lookups (RFC 7208), and each include counts.
DKIM records are different. Each provider uses its own selector names, such as fm1, fm2 and fm3 at Fastmail or protonmail, protonmail2 and protonmail3 at Proton Mail, so the new records can sit next to the old ones until you remove the old provider. Look at the published records with the commands in how to check MX, SPF, DKIM and DMARC records.
How do I know the move worked?
Send a test message to the domain from two outside accounts and read the delivery headers. According to Postelva's index of 12 November 2026, moving to Proton Mail means changing 8 records, to Mailbox.org 11 and to Fastmail 6 (the DMARC record of Fastmail was not read on the pages checked), so a check of each record type is the quickest way to find a missed one.
If a message does not arrive, the fault is nearly always one of the causes in why email is not arriving at a custom domain. Keep the old account for a few weeks, because a sender with a stale cache can still deliver there. When the old account stays empty, raise the TTL to its normal value and remove the old records.
Moving providers: questions
How long does the switch take?
A typical MX change settles in 1 to 4 hours and can take 24 to 48 hours. Proton Mail asks you to allow up to a day. A short TTL set in advance keeps the window small.
Do I lose my address when I move?
No, if the address is on your own domain: the domain stays at the same registrar and only the records change. An address at the old provider's own domain, such as @proton.me or @tuta.com, cannot move.
Can I move without importing the old mail?
You can, but you lose the archive in the new mailbox. Keep the old account open, or export the mail, until you have what you need.
Does the move change my domain registration?
No. The registration, the renewal date and the owner stay the same. Only the DNS records that point to the mail server change.
Should I move at a quiet hour?
It helps but is not required. What matters is that the MX switch happens after the import and after the TTL was lowered.
In summary
- Lower the MX TTL to 300 to 600 seconds 24 to 48 hours before the move.
- Import the archive over IMAP first; forwarding moves only new mail.
- Switch the MX records last; do not leave two providers mixed.
- One SPF record only; add the new include to it; at most 10 DNS lookups.
- Records changed: Proton Mail 8, Mailbox.org 11, Fastmail 6 without DMARC.
- Typical propagation is 1 to 4 hours, up to 24 to 48 hours.
- Keep the old account until the test mails have arrived.
Sources (8)
- Switch from Gmail to Proton — Proton (read 2026-11-12)
- Custom domain from Namecheap (MX values) — Proton (read 2026-11-12)
- Anti-spoofing for custom domains — Proton (read 2026-11-12)
- Default DNS records — Fastmail (read 2026-11-12)
- mailbox.org KB: custom domain — mailbox.org (read 2026-11-12)
- RFC 7208, section 4.6.4 — RFC Editor (read 2026-11-12)
- RFC 2308: negative caching of DNS queries — RFC Editor (read 2026-11-12)
- How long does it take for DNS changes to propagate — Suped (read 2026-11-12)