IntelliJ can't connect to its own Scala compile server
<p>I am using latest IntelliJ IDEA (2016.1.1) - <em>but I have seen this behaviour in previous versions too</em> - developing in Scala with latest Scala plugin (3.0.3).</p>

<p>When I try to Run/Debug a test or code, IDEA will start Making the project, but will then stay there several seconds while the "Make" progress bar doesn't progress at all.</p>

<p>After 20-30 seconds of this, the following message appear in the Messages tab:</p>

<blockquote>
  <p>Warning:scala: Cannot connect to compile server at
  localhost/127.0.0.1:59656 Trying to compile without it</p>
</blockquote>

<p>The port shown there, 59656, is a port I hard-coded myself in <code>%USER_PROFILE%\.IntelliJIdea2016.1\config\options\scala.xml</code>, after I noticed this problem the first time on the default port, so changing the port did not help...</p>

<p>At this point, the bar will read "Reading compilation settings..." for several more tens of seconds before the code actually runs. It is terribly bothering and I can't seem to be able to fix it definitively. This can easily take up to 3 minutes to run a single test. Very disrupting. I noticed this problem happening intermittently on my work machine (Win7). </p>

<p>Anyone has any idea how to debug/fix this issue?</p>

<p>Thanks</p>