When trying to set a persona in personalization settings, searching the add-ons Firefox site doesn't return any results, even when the search string is an empty one.
Steps to Reproduce:
1. Open Personalization settings page
2. Press "Choose Theme"
No theme is found.
Many themes should be found.
User Profile Reset: No
Using "tree" as a search work (like the example in Chapter 2 of Getting Started guide) the search does not return any themes (see Chapter 2 what it should return).
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:57.0) Gecko/20100101 Firefox/57.0
There is a general bug report about Personalization not working, but it is very vague; there one comment suggests there might be a problem with a change in Firefox add-ons repository. And similar problem is reported from different OS's.
Entering a http address of a theme pops up a message, that the theme currently cannot be opened and the user should try again later.
Here is a sample theme that does not install:
Possible DUP of bug 114772 ?
Or even a DUP of bug 114731
Or maybe even bug 101629
Well, https://bugs.documentfoundation.org/show_bug.cgi?id=114731 was a duplicate of bug #114818 and the #114731 log shows the remaining problem, as described in this bug, is a Mozilla theme/add-on site change/problem.
#114772 reports of the finding theme problem but links it to proxy not working, which might not be the case.
So either close this one or those two, the problem remains - one of UI functions is "dead" for users - themese cannot be found and thus installed at all (the function works only if user already installed a theme before November or December 2017).
So it is a major UI error and maybe fellow Mozilla developers should be asked what changed on their side.
I do not know if this is relevant at all:
See this comment -> https://bugs.documentfoundation.org/show_bug.cgi?id=114731#c3
*** This bug has been marked as a duplicate of bug 114731 ***