The mailbox may have some emails with an excessively long subject line that are not supported by Windows Phone 8. Once you have removed the suspect mail item (i.e. cleaned the mailbox or move the suspect mail to a folder that phone does not sync) the error will cease.
- Why don't my Nokia accessories appear in the accessories page on my Nokia Lumia phone?
- There are no devices listed in the accessories page of my Nokia Lumia phone. Why?
- What is the Nokia Accessories application on my Nokia Lumia with Windows Phone 8?
- How do I check if there are new updates available for my Lumia phone?
- How can I divert incoming calls on my Nokia Lumia phone?