Deeplinking in ios can't use subscribe()

I use ionic-plugin-deeplinks in my app.
this work in android correctly.
but not work in iOS correctly.
in iOS launch app but not work subscribe.
I acted on the basis of issue but not work.

ionic info:

ionic (Ionic CLI)             : 4.8.0 (/usr/local/lib/node_modules/ionic)
Ionic Framework               : @ionic/angular 4.0.0-rc.0
@angular-devkit/build-angular : 0.12.1
@angular-devkit/schematics    : 7.1.4
@angular/cli                  : 7.1.4
@ionic/angular-toolkit        : 1.2.2

cordova (Cordova CLI) : 8.1.2 (cordova-lib@8.1.1)
Cordova Platforms     : ios 4.5.5
Cordova Plugins       : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 3.0.0, (and 18 other plugins)

No one to help
Does not anyone have this problem?