Module command creation giving error message

When manually setting up a clients new wordpress subfolder site, clicking the 'create' module command returns the error:

Module Command Error
Invalid data or no response: The receiving plugin may not be activated at: https://munkypress.com

The response recorded in the module logs after turned in debug messages in the wordpress plugin is as follows:

Array
(
[0] =>
<b>Notice</b>: Array to string conversion in <b>/home/munkywpadmin/public_html/engine/wp-includes/class-wp.php</b> on line <b>294</b>

<b>Warning</b>: Cannot modify header information - headers already sent by (output started at /home/munkywpadmin/public_html/engine/wp-includes/class-wp.php:294) in <b>/home/munkywpadmin/public_html/engine/wp-includes/pluggable.php</b> on line <b>955</b>

<b>Warning</b>: Cannot modify header information - headers already sent by (output started at /home/munkywpadmin/public_html/engine/wp-includes/class-wp.php:294) in <b>/home/munkywpadmin/public_html/engine/wp-includes/pluggable.php</b> on line <b>956</b>

<b>Warning</b>: Cannot modify header information - headers already sent by (output started at /home/munkywpadmin/public_html/engine/wp-includes/class-wp.php:294) in <b>/home/munkywpadmin/public_html/engine/wp-includes/pluggable.php</b> on line <b>957</b>

<b>Notice</b>: Undefined index: nickname in <b>/home/munkywpadmin/public_html/fuel/plugins/whmcs-multisite-provisioning/whmcs-mrp.php</b> on line <b>379</b>

<b>Notice</b>: wp_new_user_notification was called with an argument that is deprecated since version 4.3.1 with no alternative available. in <b>/home/munkywpadmin/public_html/engine/wp-includes/functions.php</b> on line <b>3739</b>
{"user_name":"plentyof","install_type":"subdirectory","domain":"munkypress.com","path":"\/plentyofmeals\/","login":"plentyof","blog_id":8,"mapped_domain":"plentyofmeals.com","level":1,"success":true}
[1] => Array
(
[url] => https://munkypress.com/
[content_type] => text/html
[http_code] => 200
[header_size] => 423
[request_size] => 971
[filetime] => -1
[ssl_verify_result] => 0
[redirect_count] => 0
[total_time] => 7.435768
[namelookup_time] => 0.000113
[connect_time] => 0.000218
[pretransfer_time] => 0.020145
[size_upload] => 721
[size_download] => 1588
[speed_download] => 213
[speed_upload] => 96
[download_content_length] => -1
[upload_content_length] => 721
[starttransfer_time] => 0.424117
[redirect_time] => 0
[certinfo] => Array
(
)

[primary_ip] => 172.93.121.3
[primary_port] => 443
[local_ip] => 172.93.121.3
[local_port] => 46151
[redirect_url] =>
)

[2] =>
)

I have appropriately set up wordpress to have it's wp-content folder moved, though WHMCS seems to be getting receiving something back from Wordpress and the user and site are getting generated. What could be causing the attached message?

Thanks,