diff --git a/app/services/mailings/outbound_queue.rb b/app/services/mailings/outbound_queue.rb
index 3713bb1..07407e8 100644
--- a/app/services/mailings/outbound_queue.rb
+++ b/app/services/mailings/outbound_queue.rb
@@ -1,9 +1,10 @@
 class Mailings::OutboundQueue
   LOCK_PATH = Rails.root.join("tmp/outbound_smtp.lock")
   STAMP_PATH = Rails.root.join("tmp/outbound_last_sent")
+  ATTEMPT_PATH = Rails.root.join("tmp/outbound_last_attempt")
 
   class << self
-    attr_accessor :min_interval
+    attr_accessor :min_interval, :fail_interval
 
     def enqueue(recipient)
       recipient.with_lock do
@@ -29,7 +30,9 @@ class Mailings::OutboundQueue
         begin
           CampaignMailer.raise_delivery_errors = true
           outcome = recipient.deliver_queued!
-          stamp!
+          stamp_attempt!
+          stamp! if outcome == :sent
+          Rails.logger.info("[outbound] #{outcome} mailing=#{recipient.mailing_id} to=#{recipient.email}")
           outcome == :sent ? :sent : :deferred
         ensure
           CampaignMailer.raise_delivery_errors = false if Rails.env.development?
@@ -45,7 +48,11 @@ class Mailings::OutboundQueue
     end
 
     def next_queued
-      queued_scope.order(:updated_at, :id).first
+      queued_scope.order(
+        Arel.sql(
+          "CASE WHEN mailing_recipients.error_message IS NULL OR mailing_recipients.error_message = '' THEN 0 ELSE 1 END, mailing_recipients.updated_at ASC, mailing_recipients.id ASC"
+        )
+      ).first
     end
 
     def queued_scope
@@ -53,18 +60,17 @@ class Mailings::OutboundQueue
     end
 
     def seconds_until_next_slot
-      return 0 if min_interval.to_f <= 0
-
-      last = last_sent_at
-      return 0 if last.nil?
-
-      remaining = min_interval - (Time.current - last)
-      remaining.positive? ? remaining : 0
+      [
+        remaining(last_sent_at, min_interval),
+        remaining(last_attempt_at, fail_interval)
+      ].max
     end
 
     def reset!
       @last_sent_at = nil
+      @last_attempt_at = nil
       File.delete(stamp_path) if File.exist?(stamp_path)
+      File.delete(attempt_path) if File.exist?(attempt_path)
     rescue Errno::ENOENT
       nil
     end
@@ -74,17 +80,36 @@ class Mailings::OutboundQueue
       File.write(stamp_path, @last_sent_at.to_f.to_s)
     end
 
-    def last_sent_at
-      return @last_sent_at if @last_sent_at
-      return unless File.exist?(stamp_path)
+    def stamp_attempt!
+      @last_attempt_at = Time.current
+      File.write(attempt_path, @last_attempt_at.to_f.to_s)
+    end
 
-      @last_sent_at = Time.zone.at(Float(File.read(stamp_path)))
-    rescue ArgumentError, TypeError, Errno::ENOENT
-      nil
+    def last_sent_at
+      @last_sent_at ||= read_time(stamp_path)
+    end
+
+    def last_attempt_at
+      @last_attempt_at ||= read_time(attempt_path)
     end
 
     private
 
+    def remaining(timestamp, interval)
+      return 0 if interval.to_f <= 0 || timestamp.nil?
+
+      leftover = interval - (Time.current - timestamp)
+      leftover.positive? ? leftover : 0
+    end
+
+    def read_time(path)
+      return unless File.exist?(path)
+
+      Time.zone.at(Float(File.read(path)))
+    rescue ArgumentError, TypeError, Errno::ENOENT
+      nil
+    end
+
     def lock_path
       LOCK_PATH
     end
@@ -92,7 +117,12 @@ class Mailings::OutboundQueue
     def stamp_path
       STAMP_PATH
     end
+
+    def attempt_path
+      ATTEMPT_PATH
+    end
   end
 
-  self.min_interval = Rails.env.test? ? 0.0 : 180.0
+  self.min_interval = Rails.env.test? ? 0.0 : 60.0
+  self.fail_interval = Rails.env.test? ? 0.0 : 30.0
 end
diff --git a/test/services/mailings/outbound_queue_test.rb b/test/services/mailings/outbound_queue_test.rb
index e83a2a8..7e17392 100644
--- a/test/services/mailings/outbound_queue_test.rb
+++ b/test/services/mailings/outbound_queue_test.rb
@@ -5,6 +5,7 @@ class Mailings::OutboundQueueTest < ActiveSupport::TestCase
 
   setup do
     Mailings::OutboundQueue.min_interval = 0
+    Mailings::OutboundQueue.fail_interval = 0
     Mailings::OutboundQueue.reset!
     Mailings::SmtpGate.min_gap = 0
     Mailings::SmtpGate.backoff_base = 0
@@ -13,6 +14,7 @@ class Mailings::OutboundQueueTest < ActiveSupport::TestCase
 
   teardown do
     Mailings::OutboundQueue.min_interval = 0
+    Mailings::OutboundQueue.fail_interval = 0
     Mailings::OutboundQueue.reset!
   end