variable products are all beeing changed into simple products.

Hello,
The first thing that comes to my mind is that you should update to the latest versions of your plugins.
You might also be potentially affected by this issue documented here: https://wpml.org/errata/product-variations-not-display-variation-original-language/
We added a fix for this that should automatically display you a warning in the admin panel if this is the case.
I hope that this helps you.

Hi, I have follow up this step and not doing, so may result in performance issues. How to check?

e(): I/O warning : failed to load external entity “/data/wwwroot/www.xxxx.com/wp-content/plugins/woocommerce-multilingual/vendor/otgs/installer/repositories.xml” in /data/wwwroot/www.xxxx.com/wp-content/plugins/sitepress-multilingual-cms/vendor/otgs/installer/includes/installer.class.php on line 713

Hi, I have follow up this step and not doing, so may result in performance issues. How to check?

What do you mean by that?

The other thing that you have encountered looks like a problem on loading the repositories that we use for our installer add-on and I am not entirely sure how and why it is happening, but it should be a temporary error – you might just hide it by disabling debug in WordPress.

define('WP_DEBUG', false);
define('WP_DEBUG_DISPLAY', false);

yes. I have got: I/O warning : failed to load external entity “/data/wwwroot/www.XXX.com/wp-content/plugins/sitepress-multilingual-cms/vendor/otgs/installer/repositories.xml” in /data/wwwroot/www.XXX.com/wp-content/plugins/sitepress-multilingual-cms/vendor/otgs/installer/includes/installer.class.php on line 713

I try to vist “https://api.wpml.org/” in repositories.xml. the get:
a:1:{s:5:”error”;s:49:”Unknown or Unsupported API Call: repository_error”;}

vist: https://api.wp-types.com/ in repositories.xml. the get:
a:1:{s:5:”error”;s:49:”Unknown or Unsupported API Call: repository_error”;}

Visiting the address directly is not recommended, and it is normal to produce such results.

I still have no way to solve the problem

the “term_relationships”. The term_taxonomy_id of simple products is 3, and The term_taxonomy_id of variable products is 5. I also check with _terms and find the term_id of simple product is 3, and variable product is 5. Main Menu is 2.

Since you are still having a problem, it would be a better idea that you open a new ticket in our support forum at wpml.org, where one of our specialists could try and debug the issue and try to help you.
At this moment I don’t think that I have enough data to help you and we cannot exchange private credentials here so that I can see the problem.

Hi, I have solved this bug. Enable Template Debug Mode in woocommerce setting and then I got the bug messages: “We detected that the product_type field was set incorrectly for some product translations. This happened because the product_type taxonomy was translated. You can fix this in the woocommerce multiligual troublesshooting page. ” so I go to the “troublesshooting page” and fix this bug. Thanks for your help.

So this bug have been fixed. Thanks and for all reference.