Troubleshooting an "Allowed memory size exhausted" Error
An error message along the lines of Allowed memory size of xxxxx bytes exhausted (tried to allocate xxxx bytes) means that WHMCS has reached maximum amount of memory available to PHP on your server.
The limit is controlled by the memory_limit setting in your server's PHP configuration. To check the current memory limit setting:
Navigate to Utilities > System > PHP Info.
Scroll down until you find the memory_limit directive.
Made a note of the value in the local value column
You should increase this setting until the error is resolved - please refer to our system requirements to locate the recommended value. It may be necessary to contact your server admin/hosting provider for assistance making this PHP configuration change.
Please take this opportunity to ensure all the other System Requirements are met.