diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c
index c4d620ac8b..757fbedf99 100644
--- a/src/resolve/resolved-dns-query.c
+++ b/src/resolve/resolved-dns-query.c
@@ -133,23 +133,33 @@ static int dns_query_candidate_go(DnsQueryCandidate *c) {
         DnsTransaction *t;
         int r;
         unsigned n = 0;
+        bool notify = false;
 
         assert(c);
 
+        c->query->block_ready++;
+
         /* Start the transactions that are not started yet */
         SET_FOREACH(t, c->transactions) {
                 if (t->state != DNS_TRANSACTION_NULL)
                         continue;
 
                 r = dns_transaction_go(t);
-                if (r < 0)
+                if (r < 0) {
+                        c->query->block_ready--;
                         return r;
+                }
+                if (r == 0)
+                        /* A transaction is complete. */
+                        notify = true;
 
                 n++;
         }
 
+        c->query->block_ready--;
+
         /* If there was nothing to start, then let's proceed immediately */
-        if (n == 0)
+        if (n == 0 || notify)
                 dns_query_candidate_notify(c);
 
         return 0;
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index b20a61a401..7c966affe1 100644
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -152,8 +152,8 @@ bool dns_transaction_gc(DnsTransaction *t) {
 static uint16_t pick_new_id(Manager *m) {
         uint16_t new_id;
 
-        /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the number of
-         * transactions, and it's much lower than the space of IDs. */
+        /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the
+         * number of transactions, and it's much lower than the space of IDs. */
 
         assert_cc(TRANSACTIONS_MAX < 0xFFFF);
 
@@ -1333,6 +1333,10 @@ static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) {
 
         assert(t);
 
+        /* Returns 0 if dns_transaction_complete() has been called. In that case the transaction and query
+         * candidate objects may have been invalidated and must not be accessed. Returns 1 if the transaction
+         * has been prepared. */
+
         dns_transaction_stop_timeout(t);
 
         if (!dns_scope_network_good(t->scope)) {
@@ -1460,7 +1464,6 @@ static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) {
 }
 
 static int dns_transaction_make_packet_mdns(DnsTransaction *t) {
-
         _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
         bool add_known_answers = false;
         DnsTransaction *other;
@@ -1628,8 +1631,9 @@ int dns_transaction_go(DnsTransaction *t) {
 
         assert(t);
 
-        /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has finished
-         * now. */
+        /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has
+         * finished now. In the latter case, the transaction and query candidate objects must not be accessed.
+         */
 
         assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0);
 
@@ -1687,7 +1691,7 @@ int dns_transaction_go(DnsTransaction *t) {
                 t->state = DNS_TRANSACTION_PENDING;
 
                 log_debug("Delaying %s transaction for " USEC_FMT "us.", dns_protocol_to_string(t->scope->protocol), jitter);
-                return 0;
+                return 1;
         }
 
         /* Otherwise, we need to ask the network */