diff --git a/src/main/java/de/doubleslash/usb_led_matrix/graph/Graph.java b/src/main/java/de/doubleslash/usb_led_matrix/graph/Graph.java
index c28eec0..7fc3380 100644
--- a/src/main/java/de/doubleslash/usb_led_matrix/graph/Graph.java
+++ b/src/main/java/de/doubleslash/usb_led_matrix/graph/Graph.java
@@ -12,6 +12,7 @@
 
 import java.io.File;
 import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -44,15 +45,14 @@ public class Graph {
    private HttpClient client = HttpClient.newHttpClient();
 
    public Graph() {
-      try {
-         final InputStream input = new FileInputStream(refreshFile);
+      try (FileInputStream input = new FileInputStream(refreshFile)) {
          properties.load(input);
          final String tenantID = properties.getProperty(TENANT_ID_PROPERTY);
          if (tenantID != null) {
             tokenURI = String.format("https://login.microsoftonline.com/%s/oauth2/v2.0/token", tenantID);
          }
       } catch (IOException e) {
-         LOG.error("Could not load properties from file '{}'", refreshFile.getAbsolutePath(), e);
+         LOG.error("Error loading properties from file '{}'", refreshFile.getAbsolutePath(), e);
       }
    }
 
@@ -143,8 +143,9 @@ private HttpRequest.BodyPublisher ofFormData(final Map<Object, Object> data) {
    }
 
    private void getNewAccessToken() throws IOException, InterruptedException {
-      final InputStream input = new FileInputStream(refreshFile);
-      properties.load(input);
+      try (InputStream input = new FileInputStream(refreshFile)) {
+         properties.load(input);
+      }
 
       final Map<Object, Object> values = new HashMap<>();
 
@@ -213,6 +214,10 @@ public Color getStatusColorFromTeams() throws IOException, InterruptedException
       } catch (final IllegalArgumentException e) {
          LOG.warn("Unknown availability '{}'.", teamsStatus, e);
       }
-      return availabilityStatus.getColor();
+      if (availabilityStatus != null) {
+         return availabilityStatus.getColor();
+      } else {
+         return null;
+      }
    }
 }
diff --git a/src/main/java/de/doubleslash/usb_led_matrix/view/AuthenticationView.java b/src/main/java/de/doubleslash/usb_led_matrix/view/AuthenticationView.java
index 560e7a5..910d530 100644
--- a/src/main/java/de/doubleslash/usb_led_matrix/view/AuthenticationView.java
+++ b/src/main/java/de/doubleslash/usb_led_matrix/view/AuthenticationView.java
@@ -80,8 +80,7 @@ public void customInitialize() {
          CommandLineOptions.Dark(scene);
       }
       final String fileName = "refreshToken.txt";
-      try {
-         final InputStream input = new FileInputStream(new File(fileName));
+      try (InputStream input = new FileInputStream(new File(fileName))) {
          final Properties properties = new Properties();
          properties.load(input);
          final String tenantID = properties.getProperty("tenant_id");
@@ -136,9 +135,7 @@ public void setScene(final Scene scene) {
 
    @FXML
    void setTeamsID(ActionEvent event) {
-      final FileWriter fw;
-      try {
-         fw = new FileWriter("refreshToken.txt");
+      try (FileWriter fw = new FileWriter("refreshToken.txt")) {
          final Properties p = new Properties();
          p.setProperty("tenant_id", tenantIDTextField.getText());
          p.setProperty("client_id", clientIDTextField.getText());
@@ -183,8 +180,11 @@ public void setWebsiteCode() {
          initializeCopyButton();
 
          this.deviceCode.set(deviceCode);
-      } catch (IOException | InterruptedException e) {
+      } catch (IOException e) {
          LOG.error("Could not retrieve device code: ", e);
+      } catch (InterruptedException e) {
+         LOG.error("CurrentThread was interrupt", e);
+         Thread.currentThread().interrupt();
       }
    }
 }
diff --git a/src/main/java/de/doubleslash/usb_led_matrix/view/ConfigurationView.java b/src/main/java/de/doubleslash/usb_led_matrix/view/ConfigurationView.java
index 82b5267..562f962 100644
--- a/src/main/java/de/doubleslash/usb_led_matrix/view/ConfigurationView.java
+++ b/src/main/java/de/doubleslash/usb_led_matrix/view/ConfigurationView.java
@@ -39,7 +39,7 @@
 import java.util.Optional;
 
 public class ConfigurationView {
-   private static final int POLLING_INTERVALL_SECONDS = 10;
+   private static final long POLLING_INTERVALL_SECONDS = 10;
 
    private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
 
@@ -94,6 +94,7 @@ public class ConfigurationView {
             Thread.sleep(POLLING_INTERVALL_SECONDS * 1000);
          } catch (final InterruptedException e) {
             LOG.debug("Manual mode was interrupted.", e);
+            Thread.currentThread().interrupt();
             return;
          }
       }
@@ -111,6 +112,7 @@ public class ConfigurationView {
             Thread.sleep(POLLING_INTERVALL_SECONDS * 1000);
          } catch (final InterruptedException ie) {
             LOG.debug("MS Teams status polling was interrupted.", ie);
+            Thread.currentThread().interrupt();
             return;
          }
       }
@@ -124,6 +126,7 @@ public class ConfigurationView {
             Thread.sleep(POLLING_INTERVALL_SECONDS * 1000);
          } catch (final InterruptedException e) {
             LOG.debug("Connection check was interrupted.", e);
+            Thread.currentThread().interrupt();
             return;
          }
          turnOffAutomaticallyIfNeeded(LocalTime.now());
@@ -137,6 +140,8 @@ public class ConfigurationView {
             Thread.sleep(POLLING_INTERVALL_SECONDS * 1000);
          } catch (final InterruptedException e) {
             LOG.debug("Reconnection check was interrupted.", e);
+            Thread.currentThread().interrupt();
+
             return;
          }
          turnOffAutomaticallyIfNeeded(LocalTime.now());
@@ -154,8 +159,11 @@ protected Void call() {
                answerBody = graph.pollingForToken(model.getDeviceCode());
                LOG.debug("Polling for token. Answer was: '{}'.", answerBody);
                Thread.sleep(POLLING_INTERVALL_SECONDS * 500);
-            } catch (IOException | InterruptedException e) {
+            } catch (IOException e) {
+               LOG.error("Could not get answer from server.", e);
+            } catch (InterruptedException e) {
                LOG.error("Could not get answer from server.", e);
+               Thread.currentThread().interrupt();
             }
          }
          if (answerBody.contains("access_token")) {