Google Calendar Sync out of order - error 2016, connect to internet

It's been Google Cloud Heck month for me.

First Google Video Chat was malfunctioning. We didn't figure out the cause, but it's been better lately (thanks Justin). Then Google Reader became flaky, and the Google team was AWOL for a week.

Now Google Calendar Sync is balky (again), and I'm not the only victim. It's giving misleading "Please connect to the internet" and "error code 2016" error messages when I attempt to sync Outlook to my Google Calendar (where I also sync my iPhone via their Exchange sync service).

I've been trying to debug ...

Please connect to the internet to use Google Calendar Sync - This is an old problem and seems to have cropped up again - Calendar Help

...I tried uninstall/reinstall and deleting my Google Calendar and I tried resetting IE.

I'll check the link found in the log. I think Firesea might be on the right track. Something's timing out and Google Calendar Sync is producing a misleading error message...

... Google calendar sync log
gcal_server = https://www.google.com
gaia_server = https://www.google.com
user = myname@gmail.com
user agent = Google-SyncOL-0.9.3.5 Win-5.1/SP-3.0 Outlook-12.0.0.6316 Mode-3
Sync data file to use: 9770....75
Base time: 2009-03-17T18:51:00.000Z
Sending GET request to https://www.google.com/

calendar/feeds/default/private/full?max-results=25000&updated-min=2009-03-17T18:51:01.000Z&gsessionid=edfafdd....
SEVERE: GCalConnection::GetGCalXML -> status_code = 500, error_msg = Google Calendar Sync: Error syncing your calendar. Error code: 2016....
SEVERE: Unable to get events from GCal

My next debugging steps are:

1. Extract the magic feed url from the Outlook sync log and see what it generates.
2. Sync to a calendar on an unrelated Google account and try to see if it's account specific.
3. Turn off Exchange sync and see if the calendar will then permit Outlook sync
4. Wait for Google to fix it.

I'll have more to say on my feelings about "the Google Cloud" in an Gordon's Notes opinion post.

Update: Ok, definitely making progress. I set up a fresh, unused calendar on one of my Google Apps accounts. I was able to initiate a sync, stop the sync, then restart it. On restart the step of downloading existing data worked normally. The second sync completed. So the bug is specific to my primary gmail calendar, the one I sync via Exchange server.

Update: I went to http://m.google.com/calendar and I was unable to edit the calendar sync settings there. The checked boxes won't uncheck. I've seen this bug before and it's gone away without explanation. I've posted against an old post of mine on the Google Mobile Help forum. So now I'm thinking there are two connected bugs here.

Update: I disabled calendar sync in the iPhone calendar Exchange account settings, and, on a whim, I turned off calendar sharing as well. Then I tried http://m.google.com/calendar and this time I could uncheck all but my primary account calendar. Of course maybe a retry without disabling iPhone connections would have had the same effect. Then I (for the fourth time) removed all the items from Google Calendar for my primary gmail account. I was again able to initiate synchronization to my Gmail account, but this time I could also stop it and restart it.

During this latest work I noticed a NEW option in the iPhone settings for Google Exchange synchronization. You can now sync Google email via Exchange sync. I haven't seen this announced, so I'm guessing it's a new tweak. My hunch is that whatever Google did to enable email sync changed enough things on their exchange server that they secondarily broke the Outlook Sync.

I think I have another entry for my Synchronization is Hell list.

Update: Ok, I can now complete a full (one way) Google to Gmail Calendar sync and I can then repeat it. The key is the repeat, until now I couldn't do a repeat on my primary calendar.

I've also re-enabled my iPhone Google Exchange Calendar sync and added back the Calendars to http://m.google.com/calendar. The phone is filling up. Now I'll see what my Google Outlook sync logs say in the morning.

Except ... I'm now seeing "the user has exceeded their quota" messages in my transaction log. Could be I've stressed Google Calendar a little too much.

I'm getting warmed up for my post on what I fear the Cloud ...

Update 3/19/09: It's working again. I don't know if I really fixed anything of if Google fixed something during all my debugging attempts. I'd give it a 70% probability, because of how it played out, that turning off Exchange services, purging the calendar, then restocking it, then re-enabling Exchange services did fix the problem.

Update 3/26/09: I've been tracking the logs, and it looks like I get this error about 50% of the time now.

Update 4/21/09: After not synchronizing for a few days 2016 was back and persistent. This time it was easier to repair however. I removed all events from my Google Calendar (note I only push from Outlook to Google, I don' think bidirectional sync will ever be safe), then I opened my iPhone and waited until the corresponding iPhone calendar was empty.

I then put my iPhone in airplane mode as a convenient way to turn off all push sync events. I don't want to burden Google Calendar during the initial load. (If you try this approach and it fails I think you need to follow the more onerous disabling of iPhone sync I describe above.)

Once all downstream targets were purged I initiated a desktop sync to repopulate the Google calendar. The subsequent sync is very slow.

I think Google's Calendar app is getting more burdened and slower. My guess is that Google is cutting back on their infrastructure build-out and they're getting strained. Another reason to fear the cloud.

Update 4/22/09: I was back to the error code 2016 on my next sync, so it's still broken. I think I have to wait for Google to fix something. More posts on the old forum thread. I wonder if there's any support for this problem on paid Google Apps. Probably not since this is "beta". I did see a note on a Spanning Sync blog that they're seeing lots of bugs across multiple gCal APIs, so this looks like part of a bigger problem.

Update 4/27/09: I've tried every trick I know of, including disabling the iPhone sync service and moving the calendar from my personal account to a Google Apps domain calendar. The only difference is now when sync fails I get the "please connect to the internet" error message. If I purge the target calendar I get one good sync. I'm running out of ideas!

Update 4/27/09b: Ok, it's working again. That only took about a week to fix. Looks like another entry in my Synchronization is Hell catalog. Here's what I did in the end, with the key items in bold.

1. On my iPhone turned off Google Exchange Calendar sync.
2. On my PC turned off desktop Google Calendar Sync and deleted all data in \Local Settings\Application Data\Google\Google Calendar Sync\data_files.
3. In my target Google Calendar deleted all entries.
4. On my PC enabled Calendar archiving. I configured to archive all items > 6 months old and used File:archive to initiate a manual purge. I dropped the number of events from about 2,700 to about 600.
5. On my PC re-enabled Google Calendar sync (1 way to GCal) and did a sync. I repeated the sync a few times to ensure it was working (see support thread for details on my initial results).
6. Re-enabled iPhone Exchange calendar sync.

It's working. I'm guessing there's a practical upper limit of about 2,000 events for Google Calendar Sync.

Update 6/8/11: It worked pretty well for the past two years, but after a huge archiving of my Outlook calendar Google Calendar Sync choked again with 2016 and connect to the internet error messages. These messages simply mean it's not working. I repeated the steps form 4/27/-09 and it's good again. The sync mechanism breaks with large numbers of changes. Fortunately the "primary calendar" I sync with is in a special Google account -- deletion of a primary calendar is unthinkable for most users. Google Calendar Sync is abandonware; fortunately I expect not to need it much longer.