Blank page on /admin/?page=processbounces

PHP 7.4 /PHPlist 3.6.13

When trying to process bounces through the admin button “process bounces” on page bouncemgt, I get a blank screen. When inspecting that page I see the last line being:

Process bounces


phpList will work without Javascript, but it will be easier to use if you switch it on.

I tried to upload the admin directory to the server again, thinking there would be a corrupt file somewhere, but that did not solve the problem. Seems like Javascript not loaded. How to do that? Never had this before.

Greetz, Ron

just found out that the button “check current bounce rules” on page bouncemgt also gives a blank page.

@Ronald2404 Try enabling error reporting by changing line 9 in the file admin/init.php




That might show what is failing.

Hi Duncan,

I changed the error reporting.
the blank pages are still blank, activity log only shows sending of emails, but my hosting log shows the following error on that directory:

Backend log: PHP Notice: Undefined variable: show_dev_errors in /home/


Backend log: PHP Warning: Use of undefined constant \xe2\x80\x98USE_PHPMAILER6\xe2\x80\x99 - assumed ‘\xe2\x80\x98USE_PHPMAILER6\xe2\x80\x99’ (this will throw an Error in a future version of PHP) in /home/ on line 521\n

any other place any errors would be reported?
Page still load untill
input type=“hidden” name=“formtoken” value=“9ee0ad97bfbec92aee65a7185e9eb0a3” /></form
(form with bracket closed deleted for visibility)

and is blank after that.

@Ronald2404 If you view the html source of the blank page there might be more.

But that warning about undefined constant should be fixed. I guess that you have copied/pasted a “smart quote”. Check that line in config.php and change it to a single-quote character.

When I inspect the blank page, before the !DOCTYPE html is says: mailer.

I will fix the config, which I frankly speaking hardly ever updated since i started using PHPlist ten years ago.

fixed the config.php,
still a blank page, inspect the page still says mailer

@Ronald2404 What has changed since the last time that you ran process bounces?

The text “mailer” shouldn’t be being output, unless someone added debug code and didn’t remove it.

what has changed?
Probably updated from 3.6.12 to 3.6.13.
I downloaded from, and I did not mess with the code, just uploaded the whole package.

I inspected the database, and the new bounces are in the phplist-database. So it did download the new bounces from the mailbox. Mailbox is now empty.
I just did not get an email with the report about it. Maybe that is the mailer message?

@Ronald2404 Can you check the html for the “blank page” again with error reporting set to -1. There may well be a lot of empty lines, so I wonder whether you missed something at the end.

indeed the 2 pages seem blank, but at the end of processbounce there are some javascripts after a lot of whitespace, and the checkbouncerules also contain code which are invisible on a normal browser. I will send them by PM

@Ronald2404 phplist looks to be failing while processing bounce rules. Possibly the database queries are taking too long. You can try reducing the size of the batch used by phplist by changing this line in the file admin/processbounces.php. Change 500 to a much smaller value, say 50.

$batchSize = 500; //# @TODO make a config, to allow tweaking on bigger systems

There is a similar value in checkbouncerules.php

$numperrun = 500;

@duncanc Great, that did the trick, it is working now!
I even got an email with the marked unconfirmed users.

Thank you, Duncan, for your help!