Array to string conversion error, help wanted

hi there im pretty new to ionic and i am almost done completing my first fullfledged app but i am still getting 1 bug. since it was an error display that i have never seen before i was wondering if someone could help me with this.

html:


<ion-content padding>
  
    <div class="form-group"  name="editForm"> 
      <form #f="ngForm"  >
        
            <label>naam:</label> <br><br>
            <input type="text" [(ngModel)]="question.name" name="name"  ><br><hr>
        
            <input type="hidden" [(ngModel)]="question.module_id" name="module_id">

            <label>volgorde:</label> <br><br>
            <input type='number' [(ngModel)]="question.order"  name="order"  >
            
            <hr>
            <ion-item>
              <ion-label>mag terug?</ion-label>
              <ion-toggle name="draftToggle" [(ngModel)]="question.can_go_back" checked="{{question.can_go_back}}"  ></ion-toggle>
            </ion-item><br>
 
            <label for="question.module_id" >pagina type: </label><br><br>
            <select name="singleSelect"  class="styled-select semi-square" [(ngModel)]="question.question_type_id">
                  <option [ngValue]="1">intro</option>
                  <option [ngValue]="2">media</option>
                  <option [ngValue]="3">enkele vraag</option>
                  <option [ngValue]="4">multiplechoice</option>
                  <option [ngValue]="5">open vraag</option>
                  <option [ngValue]="6">resultaat</option>
                  <option [ngValue]="7">weel of fortune</option>
                  <option [ngValue]="8">formulier</option>
            </select><hr>

            <ion-item>
              <ion-label>opslaan als draft?</ion-label>
              <ion-toggle name="draftToggle" [(ngModel)]="question.draft" checked="{{question.draft}}" >
</iontoggle>
            </ion-item><br>
            <input type="button"   value="opslaan" class="btn btn-primary" (click)=submit(question.id)>
        </form>
      </div>
  </ion-content>

functions:

export class EditPagePage {
  public question_id = this.question_id;
  public loading: boolean = true;
  public questionsReq: QuestionsRequest[] = [];
  public question: Question = new Question();
  public arQuest: Questions = new Questions();
  

  constructor(public navCtrl: NavController, public navParams: NavParams, public questionprovider: QuestionsProvider, public alertControler: AlertController, ) {

    this.question_id = navParams.get("id");
    console.log("id: " + this.question_id)

    questionprovider.get(this.question_id)
      .subscribe(res => {
        // User has access to all labels
        this.question = res;
        console.log(res.name)
        this.loading = false;
      });
  }


  public submit() {
   
    this.questionprovider.edit(this.question )
      .subscribe(res => {
        // Disable loading
        console.log(this.question.id)
      }, err => {

        this.loading = false;
        let alert = this.alertControler.create({
          title: "kan niet opslaan",
          message: "een of meerderen velden zijn niet goed ingevult.",
          buttons: [
            {
              text: "Terug"
            }
          ]
        });
        alert.present();
      });
  }

}

provider:

  public answer: Answer = new Answer();
  public Answer: AnswersRequest[] = [];

 public editAnswer(answer) {
    
    return this.http.put<AnswersRequest>("answer/" + answer.id, answer);
  }

i think this is the code that kills my request:

  * Replace the first occurrence of a given value in the string.
     *
     * @param  string  $search
     * @param  string  $replace
     * @param  string  $subject
     * @return string
     */
    public static function replaceFirst($search, $replace, $subject)
    {
        if ($search == '') {
            return $subject;
        }

        $position = strpos($subject, $search);

        if ($position !== false) {
            return substr_replace($subject, $replace, $position, strlen($search));
        }

        return $subject;
    }

and the data that i try to send


1. answers: []
2. can_go_back: 0
3. contents: [{id: 1, title: null, description: null,…},…]
4. created_at: null
5. deleted_at: null
6. id: 1
7. module_id: 1
8. name: "Intro"
9. no_check: 0
10. order: 1
11. question_type_id: 1
12. time_limit: null
13. updated_at: null

I’m not seeing where you’re calling this potentially problematic function. Can you show that?

it was an fault im my api fixed it by loading all valuesof the on there using $fillable