Moving Ghost to a new server - and new server IP to whitelist in Mailgun account

[jdaviescoates]

Further to some of the issues with migrating Ghost to a new server that I identified in this thread (about re-creating necessary email boxes etc), I just wanted to make a note for the benefit of others that when moving Ghost to a new server you also need to whitelist your new IP address in your Mailgun account or your newsletters wont send.

You do that here: https://app.mailgun.com/app/account/security/api_keys

@staff Perhaps something about this could be added to the docs somewhere too?

[girish]

Similar thing applies to other services such as Namecheap, Cloudflare etc which have a IP whitelist for their token. Not sure where we can put all this in the docs, but I bet that will never be read

[girish]

Migration aside, maybe we should periodically check keys for validity and raise some notification