How can I be sure my iPad / iPhone can see my FileMaker Server/ Host?
If you've gotten the External Data Sources between Mobile.fp7 and the hosted files ( GoZyncConnector.fp7 and GoZync.fp7) working in Pro, they'll work on your iOS device, provided your device can see your server/host. Not being able to see the host is usually only a problem for folks testing this on their local machines (people with IP addresses beginning 192.).
To test the visibility of your FileMaker Server / Host, you don't even need GoZync, you just need FileMaker Go on your iPhone or iPad:
Switch wifi off so the device is connecting to the internet over cellular.
Open FileMaker Go and get to the main "files" screen. In the right half of the screen, click the plus sign to add a host. Enter the IP address or name of your FileMaker Host and click "save". If you see files, or get asked for an account / password, your server is visible from outside the local network.
If you host isn't visible, check out the build in help for FileMaker Pro or FileMaker Server to learn about opening ports and exposing your server. You might also consider a third party hosting provider like PointInSpace.
Making sure updating new versions works?
Here is how you can be sure that the copy of your mobile file on your devices can download new versions of itself.
1. Delete the copy of Mobile.fp7 on your iPad. Remember, renaming the mobile file is fine but: GoZync keeps a separate version number for each file name. So "Mobile.fp7" on your iPad can only download new versions of that file name: if you've renamed Mobile.fp7 to "MyFile.fp7" you need to first get a copy of "MyFile.fp7" on your iPad and the GoZync's new version routines will work with "MyFile.fp7". The rest of these instructions use "Mobile.fp7" but substitute your file name here if you've renamed it.
2. Quit FileMaker on the desktop and rename the Host folder as described above.
3. Open Mobile.fp7 locally in FileMaker Pro and visit the New File Prep layout to send a new version to the server: if you get errors you may need to double check the External Data Source references in Mobile.fp7.
4. Once you have a new copy up there, close Mobile.fp7 and email yourself a copy of Mobile.fp7: you'll open this email on your iPad and then it will be installed in FileMaker Go.
5. Now open Mobile.fpy back in FileMaker Pro (keeping the Host folder renamed to xHost) and visit the New File Prep layout to send one more new version to the server: this will be one version higher than the one you emailed yourself.
6. At this point you can return to Mobile.fp7 on your iPad and click "Check for new version", downloading the build you uploaded in step 5 above. At this point you know that the file references in Mobile point to your served files. If you get an error here it is likely because your iPad can't see your FileMaker Server: it is behind a firewall or has a private IP address. Follow the instructions in FileMaker Server's built in help to open ports or otherwise expose your server / host to the outside world.
I can't upload a new version, it says "File Can Not be Created on This Disc"
It is likely that the privilege set you're logged in as does not have export rights: either log in as a full access user or extend the privileges of the account you'd like to use.
I'm getting more records than I should be.
If you're trying to zync 10 contacts (for example) and are getting many more than that, take a look at the resulting records in table view. If you see some of the correct contacts, but then a lot of records that only have the primary key (and none of the other values) it is likely that one or more of your SetField scripts is actually setting a field in the wrong table occurrence. In this contacts example, you get extra contacts by having any one SetField step from another table's Set Field script accidentally set a filed from a Table Occurrence based on Contacts.
If, on the other hand, you see lots of real contacts in there in addition to the ones you expected, then it is likely the found set in your source that is the problem: the found set just has the wrong records. See downloading found sets for more info.