diff --git a/R/tsp.R b/R/tsp.R
index dd19d59..93dbb9f 100644
--- a/R/tsp.R
+++ b/R/tsp.R
@@ -12,14 +12,21 @@ get_timestamp_secure <- function(tsq) {
 
     if(resp$status_code == 200L) {
       tsr <- PKI::ASN1.decode(resp$body)
-      ts <- PKI::ASN1.decode(PKI::ASN1.decode(PKI::ASN1.decode(tsr[[2]][[2]])[[3]][[2]]))[[5]]
-      ts <- as.POSIXct(rawToChar(ts), format = "%Y%m%d%H%M%SZ", tz="UTC")
+      if (tsr[[1]][[1]] == 0) {
+        # PKIStatus ::= INTEGER { granted (0), grantedWithMods (1), rejection (2), waiting (3),
+        # revocationWarning (4), revocationNotification (5) }
+        ts <- PKI::ASN1.decode(PKI::ASN1.decode(PKI::ASN1.decode(tsr[[2]][[2]])[[3]][[2]]))[[5]]
+        ts <- as.POSIXct(rawToChar(ts), format = "%Y%m%d%H%M%SZ", tz="UTC")
 
-      out <- list(ts = structure(strftime(ts, "%Y-%m-%dT%H:%M:%SZ", tz="UTC"),
-                                 unix_ts = as.integer(ts),
-                                 class = "pqcrypto_timestamp"),
-                  tsr = structure(resp$body,
-                                  class = "pqcrypto_tsp_tsr"))
+        out <- list(ts = structure(strftime(ts, "%Y-%m-%dT%H:%M:%SZ", tz="UTC"),
+                                   unix_ts = as.integer(ts),
+                                   class = "pqcrypto_timestamp"),
+                    tsr = structure(resp$body,
+                                    class = "pqcrypto_tsp_tsr"))
+      } else {
+        out <- list(ts = get_timestamp(),
+                    tsr = NULL)
+      }
     } else {
       out <- list(ts = get_timestamp(),
                   tsr = NULL)