Hello.
WPML randomly modifies htaccess file and we get a 500 server error. Saving permalink settings in WP admin fixes the issue but after a couple of minutes, the issue still occurs.
Would you please test the issue is happening when only WPML Multilingual CMS and WPML String translation are active?
- IMPORTANT STEP! Create a backup of your website. Or better approach will be to test this on a copy/staging version of the website to avoid any disruption of a live website.
- Switch to the default theme such as "TwentyTwenty" by going to "WordPress Dashboard > Appearance > themes".
- Go to "WordPress Dashboard > Plugins" and deactivate all plugins except WPML and its add-ons.
- Check if you can still recreate the issue.
- If not, re-activate your plugins one by one and check the issue each time to find out the plugin that causes the problem.