504 Error when publishing a message
If you want and can, deactivate the smtp post plugin and install GD mail queue. Enable the option to process ALL email and tune the queue to send every 5 minutes in batches. Also put 20 seconds as max time per batch.
That will introduce some delay in your email sending, from 2-3 to 5 minutes for each batch. BUT you will be able to see if email sending is your problem.
I use GD mail queue because my hosting provider has a smtp out emails per hour (100). Works great.
Thank you so much for your advice ! I installed GD mail queue in place of POST SMTP, and it works again, without 504 error !
There is just one problem remaining : it seems that when you click on "ADD REPLY" to publish a new message, the plugin takes the time to prepare the list of subscribed users (by checking the Wpforo Subscribes table, I suppose) to send the notification emails, BEFORE it gives back hand and publish the message.
And when you have many subscribers as we have, it takes a VERY LONG time (around 90 seconds), so the publisher can be confused and think that his contribution has failed.
And generally, if he has the (bad) idea to refresh the page, it generates a duplicate of the message.
Dear developers of Wpforo, would it be possible to change this?
I mean, would it be possible to validate the new message BEFORE seeing after the susbscribers list?
For how many subscribers we are talking about ? 90 seconds is way too much. For how is the big forum ?
Are you sure that the delay comes from wpForo. There are some good debug tools for WP that you could install.
And you can find easily those problems.
Thanks for the link, I will check.
It may have up to 2000 subscribers for some topics.