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Which Java version are you using : Oracle or OpenJDK ?
Symbolic links problem fixed. See release notes.
PDF problem fixed, see release notes.
It's already near the top of my todo list. :)
I would be tempted to say that this is a CSS issue and that Ubooquity does not support IE (too complex and too different from other major browsers), but since it was working a few weeks ago, I don't know what to say. :(
You already tried the usual investigation steps...
This is a problem caused by iOS management of HTTP pipelining issues.
The issue has been known for years but Apple doesn't care.
I'm working on replacing the internal HTTP server used by Ubooquity. This should solve this problem, but you'll have to wait a few months.
In the meantime, you can try to enable HTTPS, it has been said to disable pipelining, thus removing the problem.
To be honest, I think this problem requires real nginx skills that I don't have. :(
Just a remark: if you already use nginx to encapsulate your connection in HTTPS, you don"t need to activate it in Ubooquity.
Another angle to attack the problem would be to try to understand why you can access the HTML code of the login page (when you get the text only page) but not the images and CSS that are linked by this login page.
You could try to open the login page and find an image link in its HTML, then try to access it directly from your browser by pasting its URL in the address bar.
Perhaps the link or the behavior of nginx could provide a clue...
Customer support service by UserEcho
Could you try launching Ubooquity with the following command line parameter ?
-Dsun.java2d.cmm=sun.java2d.cmm.kcms.KcmsServiceProviderPlace it after "java", something like: