[Resuelto] Error 502: Implicitly marking parameter $triggerItem as nullable is deprecated

Problem:
The client is experiencing a persistent 502 Bad Gateway error when editing their website with Elementor while WPML is active. Despite all plugins, themes, and WordPress core being updated, and various PHP versions (8.0 to 8.4) tested, the issue persists. The error disappears when WPML is deactivated.
Solution:
We recommend the following steps to diagnose and potentially resolve the issue:
1. **Increase PHP memory and execution time limits**: Adjust the

wp-config.php

file to increase the memory limit and execution time. This can help accommodate the resource demands of using Elementor with WPML.
2. **Enable WordPress debug mode and review logs**: Modify the

wp-config.php

to enable debugging and check the

debug.log

for specific error messages after reproducing the 502 error.
3. **Clear OPcache**: Clearing the PHP OPcache can help if old or corrupted cache files are causing issues, especially after changing PHP versions.
4. **Manually reinstall WPML**: Perform a clean reinstall of WPML to eliminate any potential corruption. Ensure to backup your site before proceeding.
5. **Conduct a plugin conflict test**: Deactivate all plugins except WPML and Elementor, and then reactivate them one by one to identify any conflicts.
If these steps do not resolve the issue, it may be due to a deeper compatibility problem between WPML, Elementor, and recent PHP versions, particularly concerning the handling of nullable types. In such cases, further detailed investigation by our support team may be necessary. We recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If the problem persists, please open a new support ticket for personalized assistance at WPML support forum.