WordPress “An error occurred, please try again”: Why a Plugin License Check Fails and How to Clear the Notice
The WordPress “An error occurred, please try again.” notice is an error notice that a premium plugin displays at the top of the admin screen when it asks its license server for verification and does not get a valid response. On a server showing this notice, the plugin was found by searching for the text, and the notice was reproduced with the same plugin by changing the license server's responses; the notice that lingers for an hour after the server recovers was resolved by deleting the retry-delay value.
Essential Blocks Pro shows this notice on every admin screen, and how long the notice stays depends on whether the license server responded with a 503 or with HTML.
1️⃣ WordPress “An error occurred”: Finding the Plugin That Displayed the Notice
WordPress Admin Screen is where the notice appears, so it looks like a WordPress core error, but the text does not exist in the WordPress core files. The text sits in a plugin's license-check code, so searching the plugins folder for it identifies the plugin that displayed the notice.
When searching for the text, distinguish the comma from the period. The version broken by a period, [An error occurred. Please try again.], is a WordPress core string: when a city search in the dashboard's [WordPress Events and News] widget fails to load event data, it appears inside the widget rather than at the top of the screen.
The core string with [later] appended is used when a file saved in the theme or plugin file editor causes an error and is rolled back, and in the Customizer. The core strings are translated in the WordPress language packs, but Essential Blocks Pro ships no translation file other than Brazilian Portuguese, so the license notice appears in English even on an admin screen set to another language.
grep -rl 'An error occurred, please try again' wp-content/plugins --include=*.phpwp-content/plugins/essential-blocks-pro/includes/Deps/WPDeveloper/Licensing/Manager.phpRun the command from the WordPress installation folder; the folder name right after wp-content/plugins in the resulting path is the plugin. Besides Essential Blocks Pro, this text is also found in the license-check code of Advanced Database Cleaner Pro and in the AI API key check code of TranslatePress.
If there are several results, check the class name of the notice box in the admin screen's page source; the Essential Blocks Pro notice uses the [essential-blocks-pro-notice] class.
2️⃣ When the Notice Appears: 503 and HTML Responses, and Timeouts
Every time an admin screen opens, Essential Blocks Pro checks whether saved license data exists and, if not, sends a verification request to the license server. The diagram below shows what happened when the admin screen was opened while only the license server's response was changed.
This notice appears for non-200 responses such as a 503, and for 200 responses whose body is HTML rather than JSON. If there is no response within 15 seconds or the connection itself fails, the cURL error message returned by WordPress is shown in the notice as is, so in that case you will see a notice with different wording.
License data saved from a valid response is kept for 3 months, and during that time no verification request is sent even if the license server has an outage, so no notice appears.
3️⃣ Removing the Notice That Remains After the Server Recovers
The notice does not disappear right away when the license server is back to normal. After a failure from a 503 or a timeout, the plugin sets a 1-hour retry delay and, during that time, sends no verification request and keeps showing the saved notice.
wp option list --search='wpdeveloper_sl_failed_http_*'option_name option_value
wpdeveloper_sl_failed_http_7838117baf19d8c92e668c95a04a2642 1792071902The value is the time the delay ends (Unix time), and the string at the end of the option name is derived from the license server's URL, so it is the same on any site using the same plugin.
wp option delete wpdeveloper_sl_failed_http_7838117baf19d8c92e668c95a04a2642Success: Deleted 'wpdeveloper_sl_failed_http_7838117baf19d8c92e668c95a04a2642' option.After deleting it, reopen the posts list: the plugin checks with the license server again, and once a valid response arrives the notice disappears. If the license server outage is still ongoing, it receives another 503 and the same notice and a new 1-hour delay are set, so delete the option only after the license server is back to normal.
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