Q: When my e-mail was hacked and I had to change my password, the + button on my iPhone Calendar app disappeared and now I cannot create events. Also when I go to Settings, Calendars there are two lines missing—there is no line regarding syncing. Can you help with this issue?
A: If you’re using an online calendar service such as iCloud, Exchange, or another CalDAV server you’ll want to ensure that this is still properly configured and enabled on your iPhone, either directly under the iCloud settings or in the Mail, Contacts, Calendars section under whatever specific Calendar service account you’re using (e.g. Gmail or another CalDAV service).
On this screen, “Calendars” should appear in the smaller print beneath the account name for any account that have Calendar synchronization enabled.
If your calendar service doesn’t appear in this list at all, it’s also possible that it may have been deleted entirely and you’ll need to re-add it by selecting the “Add Account” option. Further, if your calendar service is tied to your e-mail account, but is listed as a separate service, you may have to change the password here as well before your calendars will sync properly.
The two lines that are most likely missing from your Calendar settings are the Sync and Default Calendar options.
Sync only appears when you’re using an online Calendar service, and Default Calendar only appears when you have more than one Calendar defined. Similarly, the + button only appears in the Calendars app if you actually have a writable calendar available.
If your calendars are properly enabled in the Mail, Contacts, Calendars section and still aren’t appearing within the actual iOS Calendars app, confirm that your password is still correct, and then try toggling the “Calendars” option OFF and back ON again. This may sometimes be required to force a resync of your calendar data from an online iCloud/CalDAV or Exchange server back to your iPhone.