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.
- How do I resolve an issue if my Lumia backup reaches 96% and stops with error?
- How do I install a ringtone using the Angry Birds Roost application?
- Which version of Windows Phone does my Lumia have?
- I cannot download or get application updates when first starting the Store app on my Lumia. How can I resolve this issue?
- How do I set up voice commands on my Lumia phone?