diff --git a/src/frontend/app/service/signature-method/signature-method-modal.component.ts b/src/frontend/app/service/signature-method/signature-method-modal.component.ts
index 3c807f923296920a58bc7da6b1065b04f309a6a7..ae468670417e04feae71fe3eb8f9e8137cc0714e 100644
--- a/src/frontend/app/service/signature-method/signature-method-modal.component.ts
+++ b/src/frontend/app/service/signature-method/signature-method-modal.component.ts
@@ -1,4 +1,4 @@
-import { Component, Input, OnInit } from '@angular/core';
+import { Component, Input, OnInit, OnDestroy } from '@angular/core';
 import { LoadingController, ModalController } from '@ionic/angular';
 import { catchError, tap } from 'rxjs/operators';
 import { of } from 'rxjs';
@@ -17,7 +17,7 @@ import { FortifyAPI } from '@peculiar/fortify-client-core';
     templateUrl: 'signature-method-modal.component.html',
     styleUrls: ['./signature-method-modal.component.scss']
 })
-export class SignatureMethodModalComponent implements OnInit {
+export class SignatureMethodModalComponent implements OnInit, OnDestroy {
 
     @Input() note: string;
     @Input() signatureMode: string;
@@ -71,6 +71,13 @@ export class SignatureMethodModalComponent implements OnInit {
         await this.initFortify();
     }
 
+    async ngOnDestroy(): Promise<void> {
+        if (!this.functionsService.empty(this.api)) {
+            this.api.finish();
+            this.api = null;
+        }
+    }
+
     async initFortify() {
         this.api = new FortifyAPI(null);