苹果应用站点关联文件无法为某些用户下载

Question

A few of our users never seem to download the apple-app-site-association file no matter how many times they delete and reinstall the app.

Redirecting through universal links is essential for our sign in flow so this issue renders the app unusable for the affected users. The number of users this affects is less than 1% and we have never been able to replicate the issue ourselves

The universal links themselves work perfectly well, it is just that for whatever reason the file is never requested from our servers, I have been through the server logs in great detail and identified that the users for whom this issue occurs never request the file, even after deleting and reinstalling the app 4 or 5 times.

Is there any known issue which could cause something like this? Should I file a bug with apple? Is it possible that the users are blocking requests to a bank of ip's including ours?

I found an article about a bug in universal links last year which was preventing their correct functioning which seemed to be related to the daemon crashing, could the daemon be crashing in the case of these users?

Answer 1

As you indicate that you are not seeing the client even hit the server, this is likely due to a firewall blocking the request or the devices running versions of iOS prior to 9, which do not support Universal Linking.

If you are seeing the clients hit the server, then there are a number of potential issues:

• The user may have inadvertantly disabled Universal Linking on the device by clicking on the breadcrumb in the screen's upper right hand corner
• The user may be behind a proxy server that is spoofing the SSL cert. When this happens, the file will still be downloaded but will not be trusted by the device