Unable to import a project

Hi,
We're trying to export a xerte project from one xerte server and import it into another.
This always fails with a 'File transfer has failed' message in the user interface. Looking in the apache error log I see the following:
[Thu Feb 06 15:43:53.977862 2025] [php:notice] [pid 308995] [client REDACTED] Unable to move uploaded project file to imported file: From: To: /var/www/html/import/1389359928/1738856633Feb25Test_deployment.zip, referer: h_t_t_p_s://FQDNREDACTED/workspaceproperties.php
(Apologies I've had to mess with the URLs above as the xerte forum doesn't like me including these!)
What is the cause of this error?
Regards,
Andy

For others who get this error...
This error looks like it is caused by the upload_max_filesize and/or post_max_size limits being too small. Increasing those to larger than the file size your are trying to import fixes this.