We are building a in-house redirect server a la bitly where our marketing teams can configure their links and implement them in emails, ads etc. So a click would go like this: source > internal redirect server > firebase > app or store.
The dynamic links we redirect to are manually built and some dynamic parameters are passed on the fly by our redirect server and then captured in the mobile app.
We are currently facing an issue on iOS where firebase does not seem able to "see" the app installed on the device, when the preview page setting is off (preference of our marketing team). No problem with the preview page switched on and no problem on Android with or without preview.
We thought originally that this behaviour could be caused by the absence of some headers in our redirect, so we added all the original request headers and user agent to our response headers, but that didn't solve the problem either.
Please also note that the links are currently already used in production without any problem. Adding our own redirection layer seems to be causing these issues, on iOS, without preview. But we can't figure out why.
Any insight on why that might happen would be extremely helpful.
Thanks
Stephane