In order to expedite handling your support requests, can you please share WPML support debug information from your site?
To give debug information please follow the steps:
- login to your site and go to WPML -> Support. From there click on the “debug information” link at the bottom of the page.
- Once on the “debug information” page, select the entire text box content and copy it.
- Now go back to our support forum, find the debug information box, and paste it.
When using different domains per language on the WPML-> Language -> Language URL format section, you need to make sure that the checkbox next to "Auto sign-in and sign-out users from all domains" is checked, also below that checkbox make sure the option "Pass arguments via POST" is selected. (please check image attached)
After that click "Save", and check if the issue happens again and let me know.