diff --git a/fints4javaBankingClient/src/main/kotlin/net/dankito/banking/mapper/fints4javaModelMapper.kt b/fints4javaBankingClient/src/main/kotlin/net/dankito/banking/mapper/fints4javaModelMapper.kt
index 86706d2f..d49b748f 100644
--- a/fints4javaBankingClient/src/main/kotlin/net/dankito/banking/mapper/fints4javaModelMapper.kt
+++ b/fints4javaBankingClient/src/main/kotlin/net/dankito/banking/mapper/fints4javaModelMapper.kt
@@ -11,12 +11,16 @@ import net.dankito.fints.model.BankData
 import net.dankito.fints.model.CustomerData
 import net.dankito.fints.response.client.FinTsClientResponse
 import net.dankito.fints.response.segments.AccountType
+import net.dankito.utils.exception.ExceptionHelper
 import java.math.BigDecimal
 
 
 open class fints4javaModelMapper {
 
 
+    private val exceptionHelper = ExceptionHelper()
+
+
     open fun mapResponse(response: FinTsClientResponse): BankingClientResponse {
         return BankingClientResponse(response.isSuccessful, mapErrorToShowToUser(response), response.exception)
     }
@@ -48,7 +52,9 @@ open class fints4javaModelMapper {
     }
 
     open fun mapErrorToShowToUser(response: FinTsClientResponse): String? {
-        return response.exception?.localizedMessage ?: response.errorsToShowToUser.joinToString("\n")
+        val innerException = response.exception?.let { exception -> exceptionHelper.getInnerException(exception) }
+
+        return innerException?.localizedMessage ?: response.errorsToShowToUser.joinToString("\n")
     }