diff --git a/app/src/main/java/io/heckel/ntfy/util/Util.kt b/app/src/main/java/io/heckel/ntfy/util/Util.kt
index d987e41..d03fe92 100644
--- a/app/src/main/java/io/heckel/ntfy/util/Util.kt
+++ b/app/src/main/java/io/heckel/ntfy/util/Util.kt
@@ -443,6 +443,10 @@ fun String.readBitmapFromUriOrNull(context: Context): Bitmap? {
     }
 }
 
+fun Long.nullIfZero(): Long? {
+    return if (this == 0L) return null else this
+}
+
 // TextWatcher that only implements the afterTextChanged method
 class AfterChangedTextWatcher(val afterTextChangedFn: (s: Editable?) -> Unit) : TextWatcher {
     override fun afterTextChanged(s: Editable?) {
diff --git a/app/src/play/java/io/heckel/ntfy/firebase/FirebaseService.kt b/app/src/play/java/io/heckel/ntfy/firebase/FirebaseService.kt
index 1a367ab..830b92d 100644
--- a/app/src/play/java/io/heckel/ntfy/firebase/FirebaseService.kt
+++ b/app/src/play/java/io/heckel/ntfy/firebase/FirebaseService.kt
@@ -14,6 +14,7 @@ import io.heckel.ntfy.msg.ApiService
 import io.heckel.ntfy.msg.NotificationDispatcher
 import io.heckel.ntfy.msg.NotificationParser
 import io.heckel.ntfy.service.SubscriberService
+import io.heckel.ntfy.util.nullIfZero
 import io.heckel.ntfy.util.toPriority
 import io.heckel.ntfy.util.topicShortUrl
 import io.heckel.ntfy.work.PollWorker
@@ -94,8 +95,8 @@ class FirebaseService : FirebaseMessagingService() {
         val encoding = data["encoding"]
         val attachmentName = data["attachment_name"] ?: "attachment.bin"
         val attachmentType = data["attachment_type"]
-        val attachmentSize = data["attachment_size"]?.toLongOrNull()
-        val attachmentExpires = data["attachment_expires"]?.toLongOrNull()
+        val attachmentSize = data["attachment_size"]?.toLongOrNull()?.nullIfZero()
+        val attachmentExpires = data["attachment_expires"]?.toLongOrNull()?.nullIfZero()
         val attachmentUrl = data["attachment_url"]
         val truncated = (data["truncated"] ?: "") == "1"
         if (id == null || topic == null || message == null || timestamp == null) {
diff --git a/fastlane/metadata/android/en-US/changelog/29.txt b/fastlane/metadata/android/en-US/changelog/29.txt
index 805d904..84dd455 100644
--- a/fastlane/metadata/android/en-US/changelog/29.txt
+++ b/fastlane/metadata/android/en-US/changelog/29.txt
@@ -12,6 +12,7 @@ Bug fixes + maintenance:
 * Fix topics do not re-subscribe to Firebase after restoring from backup (#511)
 * Fix crashes from large images (#474, thanks to @daedric7 for reporting)
 * Fix notification click opens wrong subscription (#261, thanks to @SMAW for reporting)
+* Fix Firebase-only "link expired" issue (#529)
 * Add donate button (no ticket)
 
 Additional translations: