Currently you are unable to use the Microsoft Office 365 Migration tools to migrate from 1and1 Exchange server. The standard IMAP migration option appears to be blocked by 1and1.
This leaves the option of a PST manual migration. We can either do this for you or you can follow these instructions to do it yourself. This guide assumes you still have your 1and1 Exchange account running and you are using Outlook as your email client.
1. Set up your users in Office 365. Login to https://portal.office.com to check your login details.
2. Change your DNS of your domain name to point to Office 365 with the settings provided in Domains --> Setup. In general your 1and1 email settings will not include any reference to your DNS. Please check this first to make sure your have not customised your setup.
3. Your DNS settings will take a while to propogate around the internet. You can test this from the command prompt. In cmd type 'ping autodiscover.YOURDOMAINNAME' and you should get a response from outlook.com. If this is the case you can now set up your office 365 email account in Outlook.
If you are completing the process in Outlook 2010 or 2007 then please download the set up tool first. Login to https://portal.office.com and go to Settings --> Office 365 Settings.
Go to 'Install status' in the menu and then click 'Install desktop application'
Click on 'set up' button and follow the instructions. Once this is setup you can now go back to Outlook to carry on setting up your Office 365 email account.
4. Now follow this guide to set up your email account in Outlook.