diff --git a/fints4k/src/commonMain/kotlin/net/codinux/banking/fints/FinTsJobExecutor.kt b/fints4k/src/commonMain/kotlin/net/codinux/banking/fints/FinTsJobExecutor.kt
index 23519f9a..94c8e44d 100644
--- a/fints4k/src/commonMain/kotlin/net/codinux/banking/fints/FinTsJobExecutor.kt
+++ b/fints4k/src/commonMain/kotlin/net/codinux/banking/fints/FinTsJobExecutor.kt
@@ -3,6 +3,7 @@ package net.codinux.banking.fints
 import kotlinx.coroutines.delay
 import kotlinx.datetime.Instant
 import kotlinx.datetime.LocalDate
+import net.codinux.banking.fints.extensions.*
 import net.codinux.log.logger
 import net.codinux.banking.fints.messages.MessageBuilder
 import net.codinux.banking.fints.messages.MessageBuilderResult
@@ -19,9 +20,6 @@ import net.codinux.banking.fints.response.segments.*
 import net.codinux.banking.fints.tan.FlickerCodeDecoder
 import net.codinux.banking.fints.tan.TanImageDecoder
 import net.codinux.banking.fints.util.TanMethodSelector
-import net.codinux.banking.fints.extensions.minusDays
-import net.codinux.banking.fints.extensions.todayAtEuropeBerlin
-import net.codinux.banking.fints.extensions.todayAtSystemDefaultTimeZone
 import kotlin.math.max
 import kotlin.time.Duration.Companion.seconds
 
@@ -389,7 +387,14 @@ open class FinTsJobExecutor(
         while (tanChallenge.isEnteringTanDone == false) {
             delay(500)
 
-            // TODO: add a timeout of e.g. 30 min
+            // most TANs a valid 5 - 15 minutes. So terminate wait process after that time
+            if (Instant.nowExt() > tanChallenge.timestamp.plusMinutes(15)) {
+                if (tanChallenge.isEnteringTanDone == false) {
+                    tanChallenge.userDidNotEnterTan()
+                }
+
+                break
+            }
         }
 
         val enteredTanResult = tanChallenge.enterTanResult!!
diff --git a/fints4k/src/commonMain/kotlin/net/codinux/banking/fints/extensions/InstantExtensions.kt b/fints4k/src/commonMain/kotlin/net/codinux/banking/fints/extensions/InstantExtensions.kt
index a9b7d258..2e6891f7 100644
--- a/fints4k/src/commonMain/kotlin/net/codinux/banking/fints/extensions/InstantExtensions.kt
+++ b/fints4k/src/commonMain/kotlin/net/codinux/banking/fints/extensions/InstantExtensions.kt
@@ -1,8 +1,12 @@
 package net.codinux.banking.fints.extensions
 
 import kotlinx.datetime.Clock
+import kotlinx.datetime.DateTimeUnit
 import kotlinx.datetime.Instant
+import kotlinx.datetime.plus
 
 
 // should actually be named `now()`, but that name is already shadowed by deprecated Instant.Companion.now() method
-fun Instant.Companion.nowExt(): Instant = Clock.System.now()
\ No newline at end of file
+fun Instant.Companion.nowExt(): Instant = Clock.System.now()
+
+fun Instant.plusMinutes(minutes: Int) = this.plus(minutes, DateTimeUnit.MINUTE)
\ No newline at end of file