diff --git a/app/src/main/kotlin/com/simplemobiletools/dialer/helpers/CallManager.kt b/app/src/main/kotlin/com/simplemobiletools/dialer/helpers/CallManager.kt
index 57b6239c..8ff7fa19 100644
--- a/app/src/main/kotlin/com/simplemobiletools/dialer/helpers/CallManager.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/dialer/helpers/CallManager.kt
@@ -63,7 +63,7 @@ class CallManager {
                     }
                 }
                 else -> {
-                    val conference = calls.find { it.isConference() }!!
+                    val conference = calls.find { it.isConference() } ?: return NoCall
                     val secondCall = if (conference.children.size + 1 != calls.size) {
                         calls.filter { !it.isConference() }
                             .subtract(conference.children.toSet())
diff --git a/app/src/main/kotlin/com/simplemobiletools/dialer/services/SimpleCallScreeningService.kt b/app/src/main/kotlin/com/simplemobiletools/dialer/services/SimpleCallScreeningService.kt
index 068249a2..09eab9f7 100644
--- a/app/src/main/kotlin/com/simplemobiletools/dialer/services/SimpleCallScreeningService.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/dialer/services/SimpleCallScreeningService.kt
@@ -13,9 +13,9 @@ import com.simplemobiletools.commons.helpers.SimpleContactsHelper
 class SimpleCallScreeningService : CallScreeningService() {
 
     override fun onScreenCall(callDetails: Call.Details) {
-        val simpleContactsHelper = SimpleContactsHelper(this)
-        val number = Uri.decode(callDetails.handle.toString()).substringAfter("tel:")
         if (baseConfig.blockUnknownNumbers) {
+            val simpleContactsHelper = SimpleContactsHelper(this)
+            val number = Uri.decode(callDetails.handle?.toString()).substringAfter("tel:")
             val privateCursor = getMyContactsCursor(false, true)
             simpleContactsHelper.exists(number, privateCursor) { exists ->
                 respondToCall(callDetails, !exists)