Post Message Irregular Behavior

What other plugins and theme do you use on the site?

Thank you for the response.
My theme is Annon and there’re several plugins including Newsletters, Mailchimp etc.
What specific type of plugins are you referring to? Please elaborate so I can provide accurate information.

I mean all plugins you use.

Akismet Anti-Spam
Settings | Deactivate
Used by millions, Akismet is quite possibly the best way in the world to protect your blog from spam. It keeps your site protected even while you sleep. To get started, just go to your Akismet Settings page to set up your API key.

Version 4.1.5 | By Automattic | View details
Select Clever Addons
Clever Addons
Deactivate
WordPress theme framework from Zootemplate.

Version 1.0.0 | By Zootemplate | Visit plugin site
Select Clever Addons for Elementor
Clever Addons for Elementor
Settings | Deactivate | Go Pro
An ultimate addon for Elementor Page Builder. | Documentation

Version 2.0.4 | By CleverSoft | View details
Select Clever Addons Pro for Elementor
Clever Addons Pro for Elementor
Settings | Deactivate
Add premium features to Clever Addons for Elementor. | Documentation | ChangeLogs

Version 1.2.0 | By CleverSoft | Visit plugin site
Select Clever Layered Navigation
Clever Layered Navigation
Deactivate
WooCommerce AJAX Layered Navigation, WooCommerce Product Filter adds advanced product filtering to your WooCommerce shop. Documentation | ChangeLogs

Version 1.3.8 | By CleverAddon
Select Clever Swatches
Clever Swatches
Deactivate
Swatch color for your WooCommerce variable products. | Documentation | ChangeLogs

Version 2.1.9 | By cleversoft.co | Visit plugin site
Select Contact Form 7
Contact Form 7
Settings | Deactivate
Just another contact form plugin. Simple but flexible.

Version 5.1.7 | By Takayuki Miyoshi | View details
There is a new version of Contact Form 7 available. View version 5.1.8 details or update now.

Select Elementor
Elementor
Settings | Deactivate | Go Pro
The most advanced frontend drag & drop page builder. Create high-end, pixel perfect websites at record speeds. Any theme, any page, any design.

Version 2.9.8 | By Elementor.com | View details | Docs & FAQs | Video Tutorials
Select Elfsight Facebook Chat CC
Elfsight Facebook Chat CC
Deactivate | Settings | More plugins by Elfsight
Add to your site a fast and seamless communication tool for your users.

Version 1.1.0 | By Elfsight | Visit plugin site
Select Envato Market
Envato Market
Deactivate
WordPress Theme & Plugin management for the Envato Market.

Version 2.0.3 | By Envato | Visit plugin site
Select Facebook for WooCommerce
Facebook for WooCommerce
Configure | Docs | Support | Review | Deactivate
Grow your business on Facebook! Use this official plugin to help sell more of your products using Facebook. After completing the setup, you’ll be ready to create ads that promote your products and you can also create a shop section on your Page where customers can browse your products on Facebook.

Version 1.11.2 | By Facebook | View details
Select Google Analytics Dashboard for WP (GADWP)
Google Analytics Dashboard for WP (GADWP)
Settings | Support | Get ExactMetrics Pro | Documentation | Deactivate
Displays Google Analytics Reports and Real-Time Statistics in your Dashboard. Automatically inserts the tracking code in every page of your website.

Version 6.0.2 | By ExactMetrics | View details
Select Loginizer
Loginizer
Settings | Deactivate | Upgrade
Loginizer is a WordPress plugin which helps you fight against bruteforce attack by blocking login for the IP after it reaches maximum retries allowed. You can blacklist or whitelist IPs for login using Loginizer.

Version 1.4.3 | By Raj Kothari | View details
Select Maintenance
Maintenance
Settings | Deactivate
Put your site in maintenance mode, away from the public view. Use maintenance plugin if your website is in development or you need to change a few things, run an upgrade. Make it only accessible to logged in users.

Version 3.85 | By WP Maintenance | View details
Select MC4WP: Mailchimp for WordPress
MC4WP: Mailchimp for WordPress
Settings | Deactivate
Mailchimp for WordPress by ibericode. Adds various highly effective sign-up methods to your site.

Version 4.7.7 | By ibericode | View details | Documentation | Upgrade to Premium
Select Meta Box
Meta Box
Deactivate | About | Docs | Go Pro
Create custom meta boxes and custom fields in WordPress.

Version 5.3.0 | By MetaBox.io | View details
Select Newsletter
Newsletter
Deactivate
Newsletter is a cool plugin to create your own subscriber list, to send newsletters, to build your business. Before update give a look to this page to know what’s changed.

Version 6.6.5 | By Stefano Lissa & The Newsletter Team | View details
Select Product GTIN (EAN, UPC, ISBN) for WooCommerce
Product GTIN (EAN, UPC, ISBN) for WooCommerce
Deactivate | Settings
Add a Global Trade Item Number (EAN, UPC, ISBN, JAN, ITF-14) field to WooCommerce

Version 1.0.9 | By Emanuela Castorina | View details
Select Super Socializer
Super Socializer
Settings | Deactivate |
Add-Ons | Support Documentation
A complete 360 degree solution to provide all the social features like Social Login, Social Commenting, Social Sharing, Social Media follow and more

Version 7.12.41 | By Team Heateor | View details
Select W3 Total Cache
W3 Total Cache
Premium Support | Settings | Deactivate
The highest rated and most complete WordPress performance plugin. Dramatically improve the speed and user experience of your site. Add browser, page, object and database caching as well as minify and content delivery network (CDN) to WordPress.

Version 0.13.3 | By BoldGrid | View details
Select Woo Product Remover
Woo Product Remover
Deactivate
Woo Product Remover allows you to, via a single click, remove all woocommerce products from your site. It cleans up your database from products, their metadata, relationships, as well as product variations and their related meta data

Version 1.1.0 | By Mohammad Farhat | View details
Select WooCommerce
WooCommerce
Settings | Deactivate
An eCommerce toolkit that helps you sell anything. Beautifully.

Version 4.1.0 | By Automattic | View details | Docs | API docs | Premium support
Select WooCommerce Multiple Customer Addresses
WooCommerce Multiple Customer Addresses
Deactivate
Manage multiple customer shipping and billing addresses

Version 17.2 | By Lagudi Domenico
Select WP User Avatar
WP User Avatar
Deactivate | Settings
Use any image from your WordPress Media Library as a custom user avatar. Add your own Default Avatar.

Version 2.2.6 | By ProfilePress | View details | Support Forums
Select WP-DBManager
WP-DBManager
Deactivate
Manages your WordPress database. Allows you to optimize database, repair database, backup database, restore database, delete backup database , drop/empty tables and run selected queries. Supports automatic scheduling of backing up, optimizing and repairing of database.

Version 2.80.3 | By Lester ‘GaMerZ’ Chan | View details
Select WP-Optimize – Clean, Compress, Cache
WP-Optimize – Clean, Compress, Cache
Optimize | Settings | Premium | Deactivate
WP-Optimize makes your site fast and efficient. It cleans the database, compresses images and caches pages. Fast sites attract more traffic and users.

Version 3.0.19 | By David Anderson, Ruhani Rabin, Team Updraft | View details

Try switching to the default theme and deactivating all plugins excluding Contact Form 7, Akismet Anti-Spam, and WooCommerce.

Why you are advised to deactivate plugins and switch to the default theme.