IBM Traveler ’cannot connect to server’

A customer of ours had one user which suddenly couldn’t sync his iPhone or iPad with IBM Traveler (version 9.0). We tried to reset and later to delete the configuration of the device. We did this with the commands:

tell traveler reset * John Doe/HQ

and

tell traveler delete * John Doe/HQ

Reset and delete were executed, but we still got the error message ‘Cannot connect to server’ on the iPhone and iPad screen. We then tried to remove and reinstall the profile, again without success. Other accounts were working fine, so it should be an error in the mailbox, but no errors were returned in the Domino log. We upgraded the Domino server to the latest Interim Fix (IF4) as well as the Traveler addon to 9.0.0.1 IF2. Still no difference but now we got the following error in the Domino Log:

Parent ID 100 is not valid for folder with id 28244 and name ‘SubFolder’, so it will be made root folder.

When we looked in the design of the mailbox there was a folder called ‘($Inbox)\SubFolder’. When we renamed it to ‘Subfolder’, everything started to sync again. As mentioned by one of our blog readers Jon Hall, another reason can be that these users were ‘over quota’, as soon as the quota was adjusted and the device was rebooted it worked fine.