I found a bug in the way DNS entries are managed.
I updated 3 DNS entries for my domain (camping-arolla.com) in order to manage mail on gandi.net.
Works fine. I had 60 seconds TTL just for the setup/test.
- camping-arolla.com 60 IN MX 10 spool.mail.gandi.net.
- camping-arolla.com 60 IN MX 50 fb.mail.gandi.net.
- camping-arolla.com 60 IN TXT “v=spf1 include:_mailcust.gandi.net ?all”
Everithing was right, mail was working. DNS tests where OK.
Then I decided to put a proper TTL time to 3600.
As we can’t “modify” an entry, i decided to create a new one then deleted the old one.
So I had
- camping-arolla.com 60 IN MX 10 spool.mail.gandi.net.
- camping-arolla.com 60 IN MX 50 fb.mail.gandi.net.
- camping-arolla.com 60 IN TXT “v=spf1 include:_mailcust.gandi.net ?all”
- camping-arolla.com 3600 IN MX 10 spool.mail.gandi.net.
- camping-arolla.com 3600 IN MX 50 fb.mail.gandi.net.
- camping-arolla.com 3600 IN TXT “v=spf1 include:_mailcust.gandi.net ?all”
Then I deleted the old one and I got
- camping-arolla.com 3600 IN MX 10 spool.mail.gandi.net.
- camping-arolla.com 3600 IN MX 50 fb.mail.gandi.net.
- camping-arolla.com 3600 IN TXT “v=spf1 include:_mailcust.gandi.net ?all”
And the mail stoped working. No more MX entries.
After some (stressed ) testing I decided to delete the 3 entries and recreate them.
And It worked again.
So I think that deleting an entry and keeping the other one listed make the whole entry disapear, event the other one is still listed but not propagated.
Hope this helps.