Processqueue enters in a fail loop at email #95, suspends and then restarts

Hi everyone

We are experiencing an issue when trying to send a campaign through phplist 3.2.5. When we start the sending, it sends properly the first 95 emails, but then the cronjob keeps saying that it’s sending the email #95. It reports this try 1215 times, and then breaks the loop, reporting some errors.

After that, the cronjob starts again from the email #96, and sends another 95 emails. Altough it finally sends all the emails, the sending time extends innecesarily, about 3 to 5 times the normal time.

Any ideas? Here I paste the response of the cronjob. The response is obviously abridged to avoid showing the 1215 repetitions.

Our server host is Dreamhost. The cronjob command line is:
/usr/local/php56/bin/php /home/user/lists/admin/index.php -pprocessqueue -c/home/user/lists/config/config.php

Any help will be greatly appreciated

Oscar
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phpList version 3.2.5 © 2000-2016 phpList Ltd, http://www.phplist.com
phpList - Recently sent : 0
phpList - Started [0.0040290000] (98)
phpList - Sending in batches of 1000 emails [0.0003560000] (99)
phpList - Processing has started, [0.0008280000] (102)
phpList - One campaign to process. [0.0008930000] (104)
phpList - Processing message 51 [0.0082240000] (121)
phpList - Looking for subscribers [0.0016460000] (126)
phpList - Found them: 33534 to process [0.4028340000] (132)
phpList - sent 1 ETA Thu 21 Jul 05:20 sending 2678 msg/hr
phpList - sent 2 ETA Thu 21 Jul 01:59 sending 3655 msg/hr
phpList - sent 3 ETA Thu 21 Jul 00:45 sending 4223 msg/hr
.
. (abridged)
.
phpList - sent 95 ETA Sat 23 Jul 07:28 sending 535 msg/hr
phpList - sent 95 ETA Sat 23 Jul 07:31 sending 534 msg/hr
phpList - sent 95 ETA Sat 23 Jul 07:34 sending 534 msg/hr
phpList - Error: Sending of this message has been suspended [639.6104980000] (98532)
phpList - Script stage: 6 [0.0006960000] (98534)
phpList - 95 messages sent in 640.03 seconds (534 msgs/hr) [0.0009790000] (98537)
phpList - 1215 failed (will retry later) [0.0009040000] (98539)
phpList - 1 Campaign
phpList - 0 num_users_for_message
phpList - 1310 batch_count
phpList - 1000 batch_total
phpList - 1215 sendemail returned false total
phpList - 0 send blocked by domain throttle
phpList - 0 add attachment error
phpList - 1215 sendemail returned false
phpList - 0 sentastest
phpList - 0 invalid
phpList - 1215 failed_sent
phpList - 95 Sent
phpList - 1000 num_per_batch
phpList - 1 Status
phpList - 95 sent_users_for_message 51
phpList - 33534 total_users_for_message 51
phpList - 0 max_users_for_message 51
phpList - 1310 processed_users_for_message 51
phpList - 1215 failed_sent_for_message 51
phpList - Finished this run [0.0150560000] (98601)
phpList - Finished, All done [0.4882230000] (98613)

Did you ever find a solution on this?