This is just a way to remember that I've tried several hours to install a new Enterprise Portal on a Sharepoint 2013 w SP1 running on Windows 2012 R2, and been failing gracefully with different errors among which "Client found response content type of 'text/html; charset=utf-8', but expected 'text/xml'.".
I know I've seen this in the past and I have not dug very deep into the root cause of the error (EP on SP will soon be something of the past, sadly), don't recall how I've solved it then, but seems right now that something in the updates that have been pushed for SP are causing this issue.
So, over the last years I've been installing EP on SP 2013 w SP1, version 15.0.4571.1502 (KB2880552), and have not had any issues. However, these days I accepted all the proposed updates and SP got to the version 15.0.4797.1000 (with different KBs applied to several components).
Well, trying to install (the same easy way I do every time) a fresh new EP site on this latest version causes the above error. Reverting back the installs resolves the issue.
The problem is that these are security patches and I would love to apply them. On a side note, deploying an EP site using the old version and then applying the updates seems to keep the site working, so not sure if this is a fix.