diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt
index 873af5aa9..3dc494feb 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt
@@ -885,7 +885,7 @@ class ReaderActivity : BaseRxActivity<ReaderActivityBinding, ReaderPresenter>()
         binding.viewerContainer.addView(newViewer.getView())
 
         // SY -->
-        val defaultReaderType = manga.defaultReaderType(manga.mangaType(sourceName = sourceManager.getOrStub(manga.source).name))
+        val defaultReaderType = manga.defaultReaderType(manga.mangaType(sourceName = sourceManager.get(manga.source)?.name))
         if (preferences.useAutoWebtoon().get() && manga.viewer == 0 && defaultReaderType != null && defaultReaderType == ReadingModeType.WEBTOON.prefValue) {
             readingModeToast?.cancel()
             readingModeToast = this.toast(resources.getString(R.string.eh_auto_webtoon_snack)) {
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderPresenter.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderPresenter.kt
index a4197bf34..a9d140c2b 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderPresenter.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderPresenter.kt
@@ -598,7 +598,7 @@ class ReaderPresenter(
         val manga = manga ?: return preferences.defaultViewer()
         // SY -->
         return if (resolveDefault && manga.viewer == 0 && preferences.useAutoWebtoon().get()) {
-            manga.defaultReaderType(manga.mangaType(sourceName = sourceManager.getOrStub(manga.source).name)) ?: if (manga.viewer == 0) preferences.defaultViewer() else manga.viewer
+            manga.defaultReaderType(manga.mangaType(sourceName = sourceManager.get(manga.source)?.name)) ?: if (manga.viewer == 0) preferences.defaultViewer() else manga.viewer
         } else if (resolveDefault && manga.viewer == 0) {
             preferences.defaultViewer()
         } else {
diff --git a/app/src/main/java/exh/util/MangaType.kt b/app/src/main/java/exh/util/MangaType.kt
index f83f85b78..8d00e12b0 100644
--- a/app/src/main/java/exh/util/MangaType.kt
+++ b/app/src/main/java/exh/util/MangaType.kt
@@ -24,22 +24,22 @@ fun Manga.mangaType(context: Context): String {
 /**
  * The type of comic the manga is (ie. manga, manhwa, manhua)
  */
-fun Manga.mangaType(sourceName: String = Injekt.get<SourceManager>().getOrStub(source).name): MangaType {
+fun Manga.mangaType(sourceName: String? = Injekt.get<SourceManager>().get(source)?.name): MangaType {
     val currentTags = getGenres().orEmpty()
     return when {
         currentTags.any { tag -> isMangaTag(tag) } -> {
             MangaType.TYPE_MANGA
         }
-        currentTags.any { tag -> isWebtoonTag(tag) } || isWebtoonSource(sourceName) -> {
+        currentTags.any { tag -> isWebtoonTag(tag) } || sourceName?.let { isWebtoonSource(it) } == true -> {
             MangaType.TYPE_WEBTOON
         }
-        currentTags.any { tag -> isComicTag(tag) } || isComicSource(sourceName) -> {
+        currentTags.any { tag -> isComicTag(tag) } || sourceName?.let { isComicSource(it) } == true -> {
             MangaType.TYPE_COMIC
         }
-        currentTags.any { tag -> isManhuaTag(tag) } || isManhuaSource(sourceName) -> {
+        currentTags.any { tag -> isManhuaTag(tag) } || sourceName?.let { isManhuaSource(it) } == true -> {
             MangaType.TYPE_MANHUA
         }
-        currentTags.any { tag -> isManhwaTag(tag) } || isManhwaSource(sourceName) -> {
+        currentTags.any { tag -> isManhwaTag(tag) } || sourceName?.let { isManhwaSource(it) } == true -> {
             MangaType.TYPE_MANHWA
         }
         else -> {