newbie here.... go easy on me 🥴

Have inherited an invision 4 forum, just upgraded to 4.7.20 , there are few php incompatible plugins but these are all disabled...

But i've seen a big spike in system logs over the last 7 days after none for a while...

most common one is:

ValueError: DOMDocument::loadHTML(): Argument #1 ($source) must not be empty (0) #0 /var/www/html/107802/system/Xml/DOMDocument.php(52): DOMDocument->loadHTML('', 256) #1 /var/www/html/107802/applications/core/modules/front/system/serviceworker.php(100): IPS\Xml\_DOMDocument->loadHTML('', 256) #2 /var/www/html/107802/applications/core/modules/front/system/serviceworker.php(66): IPS\core\modules\front\system\_serviceworker->buildCollapsedOfflinePage() #3 /var/www/html/107802/system/Dispatcher/Controller.php(118): IPS\core\modules\front\system\_serviceworker->manage() #4 /var/www/html/107802/system/Dispatcher/Dispatcher.php(153): IPS\Dispatcher\_Controller->execute() #5 /var/www/html/107802/index.php(13): IPS\_Dispatcher->run() #6 {main}

any clues on where to start looking for the source of this issue?

thx

ben

Just below the error message, take a look at the "loaded hooks" section, which should give you a clue as to what items are likely to be the cause. For example in yours I can see you have a slack app being loaded, among others, in that location

thanks for the tip, Marc. ill take a look

13 hours ago, Ben DTL said:

any clues on where to start looking for the source of this issue?

You should look into IPS Pages hooks imo. (\IPS\core\modules\front\system\serviceworker.php)