Mailbox posting not working

Hello,

I was testing on my test environment to get the Mailbox Posting working, before I am implementing on live site.
But, It only worked twice. I have not changed the settings, but it just won't work.
When running the "Test Connection" the result is "Success".
When entering the URL:

http://www.mydomainname/portal/index.php?option=com_easyblog&;task=cron

it also seems to work:

{"emails":{"status":200,"type":"info","message":"There are no pending emails that needs to be dispatched currently."},"email_import":{"status":200,"type":"info","message":"Email service interval is not up yet. Next service is at 10 december 2018"},"twitter_import":{"status":200,"type":"info","message":"No Twitter accounts associated on the site. Skipping this"},"scheduler_publish":{"status":200,"type":"info","message":"No scheduled posts to process currently."},"scheduler_unpublish":{"status":"","type":"","message":""},"scheduler_remove_tmp_files":{"status":"","type":"","message":""},"scheduler_remove_blank_posts":{"status":200,"type":"info","message":"Blank posts removed"},"token_expiry_notification":{"status":200,"type":"success","message":"Facebook autoposting disabled. Nothing to process."},"scheduler_autopost":{"status":200,"type":"info","message":"No scheduled autoposts to process currently."},"scheduler_reposting":{"status":200,"type":"info","message":"No blog posts found for re-autoposting process currently."},"scheduler_expiry_download":{"status":200,"type":"info","message":"GDPR download disabled. Nothing to process."}}

And this is the cron job, scheduled on DirectAdmin:

/usr/bin/wget -O/dev/null "http://www.mydomainname/portal/index.php?option=com_easyblog&task=cron"

I can acces the maIlbox and see the incoming mails.

Can you help me with this?

Regards, Peter