diff --git a/pdb-ui/src/main/java/org/lucares/pdbui/InternalServerError.java b/pdb-ui/src/main/java/org/lucares/pdbui/InternalServerError.java
deleted file mode 100644
index 448f803..0000000
--- a/pdb-ui/src/main/java/org/lucares/pdbui/InternalServerError.java
+++ /dev/null
@@ -1,18 +0,0 @@
-package org.lucares.pdbui;
-
-import org.springframework.http.HttpStatus;
-import org.springframework.web.bind.annotation.ResponseStatus;
-
-@ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR, reason = "Internal Server Error")
-public class InternalServerError extends RuntimeException {
-
-	private static final long serialVersionUID = 1L;
-
-	public InternalServerError(final String message, final Throwable cause) {
-		super(message, cause);
-	}
-
-	public InternalServerError(final Throwable cause) {
-		super(cause);
-	}
-}
diff --git a/pdb-ui/src/main/java/org/lucares/pdbui/NotFoundException.java b/pdb-ui/src/main/java/org/lucares/pdbui/NotFoundException.java
new file mode 100644
index 0000000..eac3fac
--- /dev/null
+++ b/pdb-ui/src/main/java/org/lucares/pdbui/NotFoundException.java
@@ -0,0 +1,18 @@
+package org.lucares.pdbui;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(value = HttpStatus.NOT_FOUND, reason = "Not Found")
+public class NotFoundException extends RuntimeException {
+
+	private static final long serialVersionUID = 694206253376122420L;
+
+	public NotFoundException(final String message, final Throwable cause) {
+		super(message, cause);
+	}
+
+	public NotFoundException(final Throwable cause) {
+		super(cause);
+	}
+}
diff --git a/pdb-ui/src/main/java/org/lucares/pdbui/PdbController.java b/pdb-ui/src/main/java/org/lucares/pdbui/PdbController.java
index f641884..6177d5e 100644
--- a/pdb-ui/src/main/java/org/lucares/pdbui/PdbController.java
+++ b/pdb-ui/src/main/java/org/lucares/pdbui/PdbController.java
@@ -6,6 +6,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+import org.lucares.ludb.FieldNotExistsException;
 import org.lucares.ludb.Proposal;
 import org.lucares.pdb.plot.api.PlotSettings;
 import org.lucares.pdbui.domain.AutocompleteProposal;
@@ -44,48 +45,37 @@ public class PdbController implements HardcodedValues, CollectionUtils {
 			produces = MediaType.APPLICATION_JSON_UTF8_VALUE //
 	)
 	@ResponseBody
-	PlotResponse createPlot(@RequestBody final PlotRequest request) {
+	PlotResponse createPlot(@RequestBody final PlotRequest request) throws InternalPlottingException {
 
-		try {
+		final PlotSettings plotSettings = PlotSettingsTransformer.toSettings(request);
 
-			final PlotSettings plotSettings = PlotSettingsTransformer.toSettings(request);
+		final File image = plotter.plot(plotSettings);
 
-			final File image = plotter.plot(plotSettings);
-
-			final Path relativeImagePath = plotter.getOutputDir().relativize(image.toPath());
-			return new PlotResponse(WEB_IMAGE_OUTPUT_PATH + "/" + relativeImagePath.toString());
-
-		} catch (final InternalPlottingException e) {
-			throw new InternalServerError(e);
-		}
+		final Path relativeImagePath = plotter.getOutputDir().relativize(image.toPath());
+		final String relativeImgUrl = relativeImagePath.toString().replace('\\', '/');
+		return new PlotResponse(WEB_IMAGE_OUTPUT_PATH + "/" + relativeImgUrl);
 	}
 
 	@RequestMapping(path = "/autocomplete", //
 			method = RequestMethod.GET, //
-			consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE, // APPLICATION_JSON_UTF8_VALUE
+			consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE, //
 			produces = MediaType.APPLICATION_JSON_UTF8_VALUE //
 	)
 	@ResponseBody
 	AutocompleteResponse autocomplete(@RequestParam(name = "query") final String query,
 			@RequestParam(name = "caretIndex") final int caretIndex) {
 
-		try {
-			final AutocompleteResponse result = new AutocompleteResponse();
-			final int zeroBasedCaretIndex = caretIndex - 1;
+		final AutocompleteResponse result = new AutocompleteResponse();
+		final int zeroBasedCaretIndex = caretIndex - 1;
 
-			final List<Proposal> proposals = db.autocomplete(query, zeroBasedCaretIndex);
-			final List<Proposal> nonEmptyProposals = filter(proposals, p -> p.getResults() > 0);
+		final List<Proposal> proposals = db.autocomplete(query, zeroBasedCaretIndex);
+		final List<Proposal> nonEmptyProposals = filter(proposals, p -> p.getResults() > 0);
 
-			final List<AutocompleteProposal> autocompleteProposals = toAutocompleteProposals(nonEmptyProposals);
-			Collections.sort(autocompleteProposals, new AutocompleteProposalByValue());
+		final List<AutocompleteProposal> autocompleteProposals = toAutocompleteProposals(nonEmptyProposals);
+		Collections.sort(autocompleteProposals, new AutocompleteProposalByValue());
 
-			result.setProposals(autocompleteProposals);
-			return result;
-
-		} catch (final Exception e) {
-			e.printStackTrace();
-			throw new InternalServerError(e);
-		}
+		result.setProposals(autocompleteProposals);
+		return result;
 	}
 
 	@RequestMapping(path = "/fields", //
@@ -95,16 +85,9 @@ public class PdbController implements HardcodedValues, CollectionUtils {
 	)
 	@ResponseBody
 	List<String> fields() {
+		final List<String> fields = db.getDb().getFields();
 
-		try {
-			final List<String> fields = db.getDb().getFields();
-
-			return fields;
-
-		} catch (final Exception e) {
-			e.printStackTrace();
-			throw new InternalServerError(e);
-		}
+		return fields;
 	}
 
 	@RequestMapping(path = "/fields/{fieldName}/values", //
@@ -120,10 +103,8 @@ public class PdbController implements HardcodedValues, CollectionUtils {
 			final List<String> fields = db.getDb().getFieldsValues(query, fieldName);
 
 			return fields;
-
-		} catch (final Exception e) {
-			e.printStackTrace();
-			throw new InternalServerError(e);
+		} catch (final FieldNotExistsException e) {
+			throw new NotFoundException(e);
 		}
 	}
 
diff --git a/performanceDb/src/main/resources/log4j2.properties b/pdb-ui/src/main/resources/log4j2.properties
similarity index 63%
rename from performanceDb/src/main/resources/log4j2.properties
rename to pdb-ui/src/main/resources/log4j2.properties
index ac5129b..78335eb 100644
--- a/performanceDb/src/main/resources/log4j2.properties
+++ b/pdb-ui/src/main/resources/log4j2.properties
@@ -11,3 +11,6 @@ appender.console.layout.pattern = %d{yyyy-MM-dd HH:mm:ss.SSS} [%-5level] [%t] %c
  
 rootLogger.level = info
 rootLogger.appenderRef.stdout.ref = STDOUT
+
+## log all exceptions thrown by controllers. Otherwise only 500 will be logged.
+#log4j.logger.org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver=debug