Plugin conflicts
Most WordPress plugins work alongside WP Media Cloud without any issues. The conflicts that do occur fall into a small number of categories. This document covers known conflict scenarios and how to resolve them.
Running two offload plugins simultaneously#
Running WP Media Cloud alongside another media offload plugin — WP Offload Media, Media Cloud by ILAB, or Advanced Media Offloader — while both are actively offloading new uploads causes URL rewriting conflicts. Both plugins hook into WordPress attachment URL functions and will produce conflicting output depending on which runs last.
This is the most common conflict scenario. The solution is to run only one offload plugin at a time. If you are migrating from another offload plugin, complete the migration import in WP Media Cloud before deactivating the old plugin. During the migration, both plugins can be active — the old plugin handles URL rewriting for its tracked items while the migration runs. Once the migration is complete and verified, deactivate the old plugin.
See the migration documentation for step-by-step instructions:
- Migrating from WP Offload Media
- Migrating from Media Cloud by ILAB
- Migrating from Advanced Media Offloader
EWWW Easy IO CDN and WP Media Cloud CDN#
When EWWW Easy IO is configured as your CDN in WP Media Cloud, it takes over URL rewriting entirely. WP Media Cloud writes a mu-plugin and modifies wp-config.php to configure Easy IO to treat your bucket as the origin, then disables its own URL rewriting hooks. If WP Media Cloud’s CDN is set to Easy IO but Easy IO is not active or not properly initialised, URLs may not be rewritten correctly.
If you are seeing double URL rewriting — a URL that contains both a bucket hostname and an ExactDN hostname — Easy IO has not fully disabled WP Media Cloud’s own rewriting. Re-save the CDN settings in WP Media Cloud and clear any page cache. If the issue persists, confirm Easy IO is active and an ExactDN domain is assigned in EWWW settings.
If you switch away from EWWW Easy IO to a different CDN, WP Media Cloud removes the mu-plugin and reverts wp-config.php automatically on save. If leftover files remain, check wp-content/mu-plugins/ for wpmc-as3cf-shim.php or wpmc-exactdn-local-domain.php and delete them manually if present.
Smush Pro CDN#
Smush Pro includes its own CDN feature powered by the WPMU Dev CDN. If Smush Pro CDN is active at the same time as WP Media Cloud’s CDN configuration, both plugins will attempt to rewrite media URLs and may produce conflicts depending on their hook priority ordering. Use either Smush Pro CDN or WP Media Cloud’s CDN configuration, not both simultaneously.
Security plugins blocking admin-ajax.php#
WP Media Cloud’s bulk migration runs via background requests to admin-ajax.php. Security plugins that aggressively block or rate-limit requests to admin-ajax.php — including some WAF and firewall plugins — can prevent the background process from running. This manifests as a bulk migration that starts but immediately stalls.
If the bulk migration stalls and the Health tab shows a failing loopback check, check whether a security plugin is blocking loopback requests. Temporarily disable the security plugin and re-run the migration to confirm whether it is the cause. If it is, configure the security plugin to allow loopback requests to admin-ajax.php from the server’s own IP address.
Page cache plugins#
Page cache plugins do not conflict with WP Media Cloud’s URL rewriting. WP Media Cloud rewrites URLs at PHP render time, so cached pages already contain CDN URLs. However, pages cached before WP Media Cloud was configured will contain old local URLs and need to be cleared. Always clear your page cache after configuring WP Media Cloud or after completing a bulk migration.
Other attachment URL filter plugins#
Any plugin that hooks wp_get_attachment_url or wp_get_attachment_image_src runs alongside WP Media Cloud’s filters. WP Media Cloud hooks at priority 99, which runs after most plugins. A plugin hooking at a higher priority (100 or above) and rewriting URLs after WP Media Cloud may overwrite the CDN URLs WP Media Cloud produces.
If you suspect a plugin is overriding WP Media Cloud’s URL rewriting, temporarily disable plugins one at a time to identify the conflict. Once identified, check whether the conflicting plugin has a setting to disable its URL rewriting, or contact the plugin developer to ask about compatibility with cloud offload plugins.
Reporting a conflict#
If you encounter a conflict with a plugin not listed here, submit a support request from wpmediacloud.com/support with the name and version of the conflicting plugin and a description of the symptoms. Include the output from the Health tab if available.