500 ERROR CAUSED at backend

Hello,

I am using the latest version, but when I try to optimize JS and push save and purge cache, 500 error caused that I can not access backend.

Here is our site information your reference.

I suppose there is conflict with IP geo-block, or Asset clean up. but the error is same when these two plugins were disabled.

Thanks

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### WordPress Environment ###

WC Version: 3.5.2
Log Directory Writable: ✔
WP Version: ❌ 4.9.8 – There is a newer version of WordPress available (5.0.1)
WP Multisite: ✔
WP Memory Limit: 4 GB
WP Debug Mode: –
WP Cron: –
Language: en_US
External object cache: ✔

### Server Environment ###

Server Info: nginx/1.15.6
PHP Version: 7.2.12-1+ubuntu16.04.1+deb.sury.org+1
PHP Post Max Size: 100 MB
PHP Time Limit: 30
PHP Max Input Vars: 1000
cURL Version: 7.47.0
OpenSSL/1.0.2g

SUHOSIN Installed: –
MySQL Version: 5.5.5-10.1.37-MariaDB-1~xenial
Max Upload Size: 40 MB
Default Timezone is UTC: ✔
fsockopen/cURL: ✔
SoapClient: ✔
DOMDocument: ✔
GZip: ✔

### Post Type Counts ###

attachment: 50
bp-email: 20
customize_changeset: 3
mycred_email_notice: 1
nav_menu_item: 80
oembed_cache: 1
page: 181
post: 80
postman_sent_mail: 22
product: 39
revision: 79
shipping_validation: 1
shop_coupon: 38
shop_order: 250
shop_order_refund: 6
snitch: 3430
um_directory: 1
um_form: 3
wafs: 2

### Security ###

Secure connection (HTTPS): ✔
Hide errors from visitors: ✔

### Active Plugins (31) ###

Asset CleanUp: Page Speed Booster: by Gabriel Livan – 1.2.8.7
Advanced Shipping Validation for WooCommerce: by Jeroen Sormani – 1.1.3 – Not tested with the active version of WooCommerce
Flexible Checkout Fields: by WP Desk – 1.7.1
WPBakery Page Builder: by Michael M – WPBakery.com – 5.5.5
K Elements: by SeventhQueen – 4.3.5.1
Live username availability checking: by Zvere – 1.0.2
Loco Translate: by Tim Whitlock – 2.2.0
Login With Ajax: by Marcus Sykes – 3.1.7
Max Mega Menu: by megamenu.com – 2.5.2
Paid Memberships Pro: by Stranger Studios – 1.9.5.6
Paid Memberships Pro – WooCommerce Add On: by Stranger Studios – 1.6.1 – Not tested with the active version of WooCommerce
SVG Support: by Benbodhi – 2.3.15
Tumult Hype Animations: by – 1.7.4
Useso take over Google: by Bruno Xu – 1.8
Woo WeChatPay: by Alexandre Froger – 1.3
WooCommerce Advanced Free Shipping: by Jeroen Sormani – 1.1.3 – Not tested with the active version of WooCommerce
Booster for WooCommerce: by Algoritmika Ltd – 4.1.0
WooCommerce: by Automattic – 3.5.2
WP Weixin: by Alexandre Froger – 1.3
Nginx Helper: by rtCamp – 2.0.1
Redis Object Cache: by Till Krüss – 1.4.1
myCRED: by myCred – 1.7.9.7
Multisite Auth: by Samuel Elh – 0.1.4
Multisite User Management: by Brent Shepherd – 1.1
WP Widget Disable: by required – 1.9.0
SSL Insecure Content Fixer: by WebAware – 2.7.2
BuddyPress: by The BuddyPress Community – 4.1.0
Multisite Plugin Manager: by Aaron Edwards – 3.1.6
myCRED Partial Payment – WooCommerce: by Gabriel S Merovingi – 1.1 – Not tested with the active version of WooCommerce
Snitch: by pluginkollektiv – 1.1.7
IP Geo Block: by tokkonopapa – 3.0.17

### Settings ###

API Enabled: –
Force SSL: ✔
Currency: HKD ()
Currency Position: left
Thousand Separator: ,
Decimal Separator: .
Number of Decimals: 2
Taxonomies: Product Types: external (external)
grouped (grouped)
simple (simple)
variable (variable)

Taxonomies: Product Visibility: exclude-from-catalog (exclude-from-catalog)
exclude-from-search (exclude-from-search)
featured (featured)
outofstock (outofstock)
rated-1 (rated-1)
rated-2 (rated-2)
rated-3 (rated-3)
rated-4 (rated-4)
rated-5 (rated-5)

### WC Pages ###

Shop base: #17 – /shop/
Cart: #18 – /cart/
Checkout: #19 – /checkout/
My account: #20 – /my-account/
Terms and conditions: ❌ Page not set

### Theme ###

Name: Kleo Child
Version: – 0 is available
Author URL: http://seventhqueen.com
Child Theme: ✔
Parent Theme Name: Kleo
Parent Theme Version: 4.4.3
Parent Theme Author URL: http://themeforest.net/user/SeventhQueen
WooCommerce Support: ✔

### Templates ###

Overrides: kleo/woocommerce/cart/cart.php
kleo/woocommerce/cart/cross-sells.php
kleo/woocommerce/checkout/form-checkout.php
kleo/woocommerce/content-product.php
kleo/woocommerce/content-single-product.php
kleo/woocommerce/loop/loop-start.php
kleo/woocommerce/myaccount/my-address.php
kleo/woocommerce/product-searchform.php
kleo/woocommerce/single-product/product-image.php
kleo/woocommerce/single-product/product-thumbnails.php
kleo/woocommerce/single-product/related.php
kleo/woocommerce/single-product/tabs/tabs.php
kleo/woocommerce/single-product/up-sells.php

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