Cannot save model (BPNA modeller) Ajax Error - Cannot load resource

Please check the Drupal logs what's going wrong.

Thanks for quick response. I've tried ECA in D10.3.14 and D11.1, Plesk and cPanel platforms and with different browsers. Same error each time. Here is the Drupal log message from D10.3.14:

Deprecated function: ini_set(): session.sid_bits_per_character INI setting is deprecated in Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->setOptions() (line 374 of /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php)
#0 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/includes/bootstrap.inc(166): _drupal_error_handler_real()
#1 [internal function]: _drupal_error_handler()
#2 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php(374): ini_set()
#3 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/Session/SessionManager.php(120): Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->setOptions()
#4 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/vendor/symfony/http-foundation/Session/Session.php(59): Drupal\Core\Session\SessionManager->start()
#5 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/StackMiddleware/Session.php(81): Symfony\Component\HttpFoundation\Session\Session->start()
#6 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/StackMiddleware/Session.php(50): Drupal\Core\StackMiddleware\Session->initializePersistentSession()
#7 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(48): Drupal\Core\StackMiddleware\Session->handle()
#8 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/StackMiddleware/ContentLength.php(28): Drupal\Core\StackMiddleware\KernelPreHandle->handle()
#9 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/modules/big_pipe/src/StackMiddleware/ContentLength.php(32): Drupal\Core\StackMiddleware\ContentLength->handle()
#10 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\big_pipe\StackMiddleware\ContentLength->handle()
#11 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass()
#12 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(48): Drupal\page_cache\StackMiddleware\PageCache->handle()
#13 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(51): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle()
#14 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/StackMiddleware/AjaxPageState.php(36): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle()
#15 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/StackMiddleware/StackedHttpKernel.php(51): Drupal\Core\StackMiddleware\AjaxPageState->handle()
#16 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/core/lib/Drupal/Core/DrupalKernel.php(741): Drupal\Core\StackMiddleware\StackedHttpKernel->handle()
#17 /var/www/vhosts/ransomedhealedrestoredforgiven.com/httpdocs/d10314x/index.php(19): Drupal\Core\DrupalKernel->handle()
#18 {main}

That error is unrelated to ECA, there is something wrong with handling sessions. Maybe it's caused by the usage of the deprecated function mentioned in the first line. That could be coming from the setup of the site, but i can't tell for sure.

Thanks.
Any ideas on where to go on this?
You mention site setup. All the sites have 'out-of-the-box' install parameters. Can you think of anything that I should look at? E.g memory limit.
I get this error on another site with D10.3 with a lot of modules installed, including Rules. No other module gives this type of error. And also with D11.2 The error occurs with two separate versions of MariaDB. Does ECA/BPNA have any php version requirement over and above that for core? Could the issue be with BPNA? Is it worth trying another modeller, if so which would you recommend?
Thank you for your help so far on this.

I can't tell, but why not going to the latest versions for all components first, i.e. drupal 10.5 or 11.2, php 8.3, etc.

Then you may want to check settings.php etc. and clean things to, because ini_set is certainly not used by any official code that chines from Drupal. And that's the deprecated function that's called. But still, of that's removed, that's not yet telling that the problem will be solved.

One more thought: in some very rare cases i remember reports from users that one of the Apache security modules can cause trouble with Ajax requests. In that case there might also be error messages in the Apache log.

Thanks so much for this.
I found a post 💬 cannot save bpmn.io model Closed: works as designed where you say problems may arise if ECS or BPNA if not composer installed. All the sites exhibiting this problem where manually instally from .zip files. So, I'll re-install on a fresh Drupal site via composer.
I'll post again when I've tried the various options set out above.

That's for sure. And even Drupal itself dies not support other installation methods than composer anymore. It's impossible to manage all the dependencies without composer anymore. However, the error message doesn't indicate a relationship to this. Still, i strongly recommend going the composer only route.

My problem is solved.

As you suggested... php 8.5, D10.5.2, composer install of ECA and BPMN.

Thanks for your help. I'm looking forward to exploring this fantastic tool to meet business requirements without coding!

Thank you for your feedback.

Just curious, have you really switched to PHP 8.5? I'm asking because that seems a bit too far ahead. The current most used PHP version is 8.3, and 8.5 is not even publicly available, see https://www.php.net/supported-versions

Sorry, my mistake - corrected above. php 8.4!