Objective-C SDK crash

Yes, I installed it by manually following the steps of the pod file of the "CocoaPods" installation method.

Yes, the crash occurs during the "handle redirect back into SDK". The code I use for managing the redirect is the following (it is a method of the app delegate):

- (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary<UIApplicationOpenURLOptionsKey, id> *)options {
    DBOAuthCompletion completion = ^(DBOAuthResult *authResult) {
        if (authResult != nil) {
            if ([authResult isSuccess]) {
                // update the flag
                self.automaticallyUpdateDropboxInfo = YES;
            }
            else if ([authResult isCancel]) {
                // log
                // ...
            }
            else if ([authResult isError]) {
                // log
                // ...
            }
        }
    };
    BOOL canHandle = [DBClientsManager handleRedirectURL:url completion:completion];
    return canHandle;
}

I also add the code I use to begin the authorization flow. I don't think it is the problem, but who knows... The code is the following:

- (void)linkUser {
    DBScopeRequest *scopeRequest = [[DBScopeRequest alloc] initWithScopeType:DBScopeTypeUser
                                                                      scopes:@[@"account_info.read",
                                                                               @"files.metadata.read",
                                                                               @"files.metadata.write",
                                                                               @"files.content.read",
                                                                               @"files.content.write"]
                                                        includeGrantedScopes:NO];
    [DBClientsManager authorizeFromControllerV2:[UIApplication sharedApplication]
                                     controller:[self getRootViewController]
                          loadingStatusDelegate:nil
                                        openURL:^(NSURL *url) {
                                                      [[UIApplication sharedApplication] openURL:url
                                                            options:[NSDictionary dictionary] completionHandler:nil];
                                                }
                                   scopeRequest:scopeRequest];
}

Please help, I am stuck on this since a week... Thank you very much,

    Mario