ERROR: CREATE_ORDER:RuntimeException: Invalid response

I’m using your WP Let’s Encrypt plugin but the following error is generated:

ERROR: CREATE_ORDER:RuntimeException: Invalid response, header: {"server":"nginx","date":"Mon, 20 Jan 2020 06:55:37 GMT","content-type":"application\/problem+json","content-length":"111","cache-control":"public, max-age=0, no-cache","link":";rel=\"index\""} in /home/ubiquitous/public_html/wp-content/plugins/wp-letsencrypt-ssl/lib/LEConnector.php:190
Stack trace:
#0 /home/ubiquitous/public_html/wp-content/plugins/wp-letsencrypt-ssl/lib/LEConnector.php(214): WPLEClient\WPLEConnector->request('GET', 'https://acme-v0...')
#1 /home/ubiquitous/public_html/wp-content/plugins/wp-letsencrypt-ssl/lib/LEOrder.php(100): WPLEClient\WPLEConnector->get('https://acme-v0...')
#2 /home/ubiquitous/public_html/wp-content/plugins/wp-letsencrypt-ssl/lib/LEClient.php(172): WPLEClient\LEOrder->__construct(Object(WPLEClient\WPLEConnector), 1, Array, 'ubiquitousnetwo...', Array, 'rsa-4096', '', '')
#3 /home/ubiquitous/public_html/wp-content/plugins/wp-letsencrypt-ssl/classes/le-core.php(123): WPLEClient\WPLEClient->getOrCreateOrder('ubiquitousnetwo...', Array)
#4 /home/ubiquitous/public_html/wp-content/plugins/wp-letsencrypt-ssl/classes/le-core.php(80): WPLE_Core->wple_generate_order()
#5 /home/ubiquitous/public_html/wp-content/plugins/wp-letsencrypt-ssl/classes/le-core.php(64): WPLE_Core->wple_generate_verify_ssl()
#6 /home/ubiquitous/public_html/wp-content/plugins/wp-letsencrypt-ssl/admin/le_admin.php(360): WPLE_Core->__construct(Array)
#7 /home/ubiquitous/public_html/wp-includes/class-wp-hook.php(288): WPLE_Admin->wple_save_email_generate_certs('')
#8 /home/ubiquitous/public_html/wp-includes/class-wp-hook.php(312): WP_Hook->apply_filters(NULL, Array)
#9 /home/ubiquitous/public_html/wp-includes/plugin.php(478): WP_Hook->do_action(Array)
#10 /home/ubiquitous/public_html/wp-admin/admin.php(170): do_action('admin_init')
#11 {main}

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