diff --git a/flow-server/src/main/java/com/vaadin/flow/server/frontend/scanner/FrontendDependencies.java b/flow-server/src/main/java/com/vaadin/flow/server/frontend/scanner/FrontendDependencies.java
index c524d72d11c..a8f2503715d 100644
--- a/flow-server/src/main/java/com/vaadin/flow/server/frontend/scanner/FrontendDependencies.java
+++ b/flow-server/src/main/java/com/vaadin/flow/server/frontend/scanner/FrontendDependencies.java
@@ -457,14 +457,19 @@ private void computePwaConfiguration() throws ClassNotFoundException {
                 .getAnnotatedClasses(PWA.class.getName())) {
             if (!Arrays.asList(hopefullyAppShellClass.getInterfaces())
                     .contains(appShellConfiguratorClass)) {
-                throw new IllegalStateException(ERROR_INVALID_PWA_ANNOTATION);
+                throw new IllegalStateException(ERROR_INVALID_PWA_ANNOTATION
+                        + " " + hopefullyAppShellClass.getName()
+                        + " does not implement "
+                        + AppShellConfigurator.class.getSimpleName());
             }
             pwaVisitor.visitClass(hopefullyAppShellClass.getName());
         }
 
         Set<String> dependencies = pwaVisitor.getValues("name");
         if (dependencies.size() > 1) {
-            throw new IllegalStateException(ERROR_INVALID_PWA_ANNOTATION);
+            throw new IllegalStateException(ERROR_INVALID_PWA_ANNOTATION
+                    + " Found " + dependencies.size() + " implementations: "
+                    + dependencies);
         }
         if (dependencies.isEmpty()) {
             this.pwaConfiguration = new PwaConfiguration(useV14Bootstrap);
diff --git a/flow-server/src/main/java/com/vaadin/flow/server/frontend/scanner/FullDependenciesScanner.java b/flow-server/src/main/java/com/vaadin/flow/server/frontend/scanner/FullDependenciesScanner.java
index 26c7f32bab3..4256f253b00 100644
--- a/flow-server/src/main/java/com/vaadin/flow/server/frontend/scanner/FullDependenciesScanner.java
+++ b/flow-server/src/main/java/com/vaadin/flow/server/frontend/scanner/FullDependenciesScanner.java
@@ -492,7 +492,9 @@ private PwaConfiguration discoverPwa() {
             if (annotatedClasses.isEmpty()) {
                 return new PwaConfiguration(useV14Bootstrap);
             } else if (annotatedClasses.size() != 1) {
-                throw new IllegalStateException(ERROR_INVALID_PWA_ANNOTATION);
+                throw new IllegalStateException(ERROR_INVALID_PWA_ANNOTATION
+                        + " Found " + annotatedClasses.size()
+                        + " implementations: " + annotatedClasses);
             }
 
             Class<?> hopefullyAppShellClass = annotatedClasses.iterator()
@@ -501,7 +503,10 @@ private PwaConfiguration discoverPwa() {
                     && !Arrays.stream(hopefullyAppShellClass.getInterfaces())
                             .map(Class::getName).collect(Collectors.toList())
                             .contains(AppShellConfigurator.class.getName())) {
-                throw new IllegalStateException(ERROR_INVALID_PWA_ANNOTATION);
+                throw new IllegalStateException(ERROR_INVALID_PWA_ANNOTATION
+                        + " " + hopefullyAppShellClass.getName()
+                        + " does not implement "
+                        + AppShellConfigurator.class.getSimpleName());
             }
 
             Annotation pwa = annotationFinder