“Start Quizz” doesn’t show the questions

Hi, we are evaluating this plugin for our new customers.

In our test, the enrolled student can choose the course and study all the lessons.

But when the “Start Quizz” button is pressed, the time starts, but the it doesn’t show any question.

I paste the system infos, can anybody help us before we buy it?
Thanks

Javascript console
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JQMIGRATE: Migrate is installed with logging active, version 1.4.1 jquery-migrate.js:23:2
Review Methods Bound

JQMIGRATE: jQuery.parseJSON requires a valid JSON string jquery-migrate.js:45:4
console.trace(): jquery-migrate.js:47
migrateWarn https://localhost:8080/ot_elearning/wp-includes/js/jquery/jquery-migrate.js:47:5
jQuery.parseJSON https://localhost:8080/ot_elearning/wp-includes/js/jquery/jquery-migrate.js:304:3
Xb https://localhost:8080/ot_elearning/wp-includes/js/jquery/jquery.js:4:18959
y https://localhost:8080/ot_elearning/wp-includes/js/jquery/jquery.js:4:22405
.send/c https://localhost:8080/ot_elearning/wp-includes/js/jquery/jquery.js:4:26925

XHR response: 200
curl “https://localhost:8080/ot_elearning/wp-admin/admin-ajax.php” -H “Host: localhost:8080” -H “User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0” -H “Accept: application/json, text/javascript, */*; q=0.01” -H “Accept-Language: hu-HU,hu;q=0.8,en-US;q=0.5,en;q=0.3” –compressed -H “Referer: https://localhost:8080/ot_elearning/llms_quiz/player-quizz-1/” -H “Content-Type: application/x-www-form-urlencoded; charset=UTF-8” -H “X-Requested-With: XMLHttpRequest” -H “Cookie: wordpress_2dd0ec6082dec4c7f01cfa0ba06b6f4e=student_1″%”40fiscet.it”%”7C1492415052″%”7Ce8TixeGvg2tlP4x0KYDlsPmqjqd62vpkitlsrX0uCcQ”%”7C1686a1ea012f142b9243869d6076a1dfb9d05ebb052622dffb7656ae0c816284; llms_wp_session=f8cc3056096c0a01c63d9039d48274af”%”7C”%”7C1491248635″%”7C”%”7C1550821435; wordpress_test_cookie=WP+Cookie+check; wordpress_logged_in_2dd0ec6082dec4c7f01cfa0ba06b6f4e=student_1″%”40fiscet.it”%”7C1492415052″%”7Ce8TixeGvg2tlP4x0KYDlsPmqjqd62vpkitlsrX0uCcQ”%”7Cd0ccac9423358f367e3b7da77d9ef4e23e25e22ee04edbae927320f5115be7cd” -H “Connection: keep-alive” –data “action=start_quiz&quiz_id=32&user_id=2”

Wordpress
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Home Url: https://localhost:8080/ot_elearning
Site Url: https://localhost:8080/ot_elearning
Version: 4.7.3
Debug Mode: No
Locale: en_GB
Multisite: No
Page For Posts: Not Set
Page On Front: Home (#1)
Permalink Structure: /%postname%/
Show On Front: page
Wp Cron: Yes

Settings
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Version: 3.6.1
Db Version: 3.6.1
Course Catalog: Courses (#6)
Course Catalog Per Page: 10
Course Catalog Sorting: menu_order,ASC
Membership Catalog:(#5)
Membership Catalog Per Page: 10
Membership Catalog Sorting: menu_order,ASC
Site Membership: Not Set
Student Dashboard:(#7)
Courses Endpoint: my-courses
Edit Endpoint: edit-account
Lost Password Endpoint: lost-password
Vouchers Endpoint: redeem-voucher
Autogenerate Username: yes
Password Strength Meter: yes
Minimum Password Strength: strong
Terms Required: no
Terms Page: Not Set
Checkout Names: required
Checkout Address: required
Checkout Phone: optional
Checkout Email Confirmation: yes
Open Registration: no
Registration Names: required
Registration Address: optional
Registration Phone: hidden
Registration Voucher: optional
Registration Email Confirmation: no
Account Names: required
Account Address: required
Account Phone: optional
Account Email Confirmation: yes
Checkout Page: Courses (#6)
Confirmation Endpoint: confirm-payment
Force Ssl Checkout: no
Country: US
Currency: EUR
Currency Position: left
Thousand Separator: ,
Decimal Separator: .
Decimals: 2
Trim Zero Decimals: no
Recurring Payments: no
Email From Address: xxx
Email From Name: xxx
Email Footer Text:
Email Header Image:
Cert Bg Width: 800
Cert Bg Height: 616
Cert Legacy Compat: no

Gateways
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Manual: Enabled
Manual Logging:
Manual Order: 1

Server
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Mysql Version: 5.7.14
Php Curl: Yes
Php Default Timezone: UTC
Php Fsockopen: Yes
Php Max Input Vars: 2500
Php Max Upload Size: 256 MB
Php Memory Limit: 256M
Php Post Max Size: 256M
Php Soap: Yes
Php Suhosin: No
Php Time Limt: 120
Php Version: 7.0.10
Software: Apache/2.4.23 (Win64) PHP/7.0.10
Wp Memory Limit: 40M

Theme
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Name: Twenty Seventeen Child
Version: 1.1
Themeuri:
Authoruri:
Template: twentyseventeen
Child Theme: Yes
Llms Support: No

Plugins
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Advanced Database Cleaner: 2.0.0
LifterLMS: 3.6.1
Quizz_importer42: 1.0.0
WebVTT: 1.3.2
WordPress Importer: 0.6.3
WP Duplicate posts pages & CPT: 1.0

Integrations
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BbPress: No
BuddyPress: No