diff --git a/src/app/test-controller/backend.service.ts b/src/app/test-controller/backend.service.ts
index a4613b01781e75f11e547261323e0aef1f95b901..cc481e275694e6c31facbbacac00a69eb23c6260 100644
--- a/src/app/test-controller/backend.service.ts
+++ b/src/app/test-controller/backend.service.ts
@@ -76,7 +76,13 @@ export class BackendService {
 
   // ------------------------------
   getResource(resId: string): Observable<string | ServerError> {
-    return this.http.get<string>(this.serverSlimUrl_GET + 'resource/' + resId)
+    const myHttpOptions = {
+        headers: new HttpHeaders({
+          'Content-Type':  'application/json'
+        }),
+        responseType: 'text' as 'json'
+    };
+    return this.http.get<string>(this.serverSlimUrl_GET + 'resource/' + resId, myHttpOptions)
       .pipe(
         catchError(this.handle)
       );
diff --git a/src/app/test-controller/test-controller.component.ts b/src/app/test-controller/test-controller.component.ts
index 5ab7c5482028d63af3c225c2df12277eaae9ba3f..c25efe7bc99623f72e3be7e58c4fbee2d4d3b263 100644
--- a/src/app/test-controller/test-controller.component.ts
+++ b/src/app/test-controller/test-controller.component.ts
@@ -151,6 +151,7 @@ export class TestControllerComponent implements OnInit, OnDestroy {
           .pipe(
             switchMap(myData => {
               if (myData instanceof ServerError) {
+                console.log('## problem getting player "' + playerId + '"');
                 return of(false);
               } else {
                 const player = myData as string;
@@ -158,6 +159,7 @@ export class TestControllerComponent implements OnInit, OnDestroy {
                   this.tcs.addPlayer(playerId, player);
                   return of(true);
                 } else {
+                  console.log('## size of player "' + playerId + '" = 0');
                   return of(false);
                 }
               }
@@ -220,6 +222,7 @@ export class TestControllerComponent implements OnInit, OnDestroy {
                     return this.bs.getResource(definitionRef).pipe(
                       switchMap(def => {
                         if (def instanceof ServerError) {
+                          console.log('error getting unit "' + myUnit.id + '": getting "' + definitionRef + '" failed');
                           return of(false);
                         } else {
                           this.tcs.addUnitDefinition(sequenceId, def as string);
@@ -268,10 +271,14 @@ export class TestControllerComponent implements OnInit, OnDestroy {
 
               const myUnitLoadings = [];
               for (let i = 1; i < this.tcs.numberOfUnits + 1; i++) {
-                myUnitLoadings.push(this.loadUnitOk(this.tcs.rootTestlet.getUnitAt(i).unitDef, i));
+                const ud = this.tcs.rootTestlet.getUnitAt(i);
+                if (ud === null) {
+                  console.log('# yo hm: ' + i.toString());
+                } else {
+                  myUnitLoadings.push(this.loadUnitOk(ud.unitDef, i));
+                }
               }
               forkJoin(myUnitLoadings).subscribe(allOk => {
-                console.log('# yo hm');
                 console.log(allOk);
               });
             }