I have tried to install the Export Metadata on Omeka S, but posterior to installation I got the error: Laminas\ServiceManager\Exception\ServiceNotCreatedException
Service with name “Omeka\Cli” could not be created. Reason: Neither “proc_open()” nor “exec()” are available.
This error means that your server has disabled both functions Omeka S uses to run “background” jobs. To do things that need those kinds of long-running background jobs, you’ll need to see if you can get your server administration to allow one of the two functions mentioned in the error message, or look at changing to a host that doesn’t block this.