Could you provide the Saros log? It can be found in the workspace of the project: <workspace>/.metadata/.plugins/saros.eclipse/log/<date>/*.log
Also, are you using any other IDE plugins (especially ones adding support for other programming languages; those have caused trouble in the past) in combination with Saros?
When building sarosServer from Source I receive the following error-message
$ ./gradlew sarosServer
Task :buildSrc:compileJava UP-TO-DATE
Task :buildSrc:compileGroovy NO-SOURCE
Task :buildSrc:pluginDescriptors UP-TO-DATE
Task :buildSrc:processResources UP-TO-DATE
Task :buildSrc:classes UP-TO-DATE
Task :buildSrc:jar UP-TO-DATE
Task :buildSrc:assemble UP-TO-DATE
Task :buildSrc:pluginUnderTestMetadata UP-TO-DATE
Task :buildSrc:compileTestJava NO-SOURCE
Task :buildSrc:compileTestGroovy NO-SOURCE
Task :buildSrc:processTestResources NO-SOURCE
Task :buildSrc:testClasses UP-TO-DATE
Task :buildSrc:test NO-SOURCE
Task :buildSrc:validatePlugins UP-TO-DATE
Task :buildSrc:check UP-TO-DATE
Task :buildSrc:build UP-TO-DATE
FAILURE: Build failed with an exception.
What went wrong:
A problem occurred configuring project ':saros.eclipse'.
Failed to notify project evaluation listener.
Could not initialize class com.diffplug.gradle.FileMisc
Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
Get more help at https://help.gradle.org
Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.1/userguide/command_line_interface.html#sec:command_line_warnings
BUILD FAILED in 2s