HI Kiran,
thank you. I was able to solve the problem. You were right about your guess. The culprit was an update of WPML itself.
Here are some infos for similar requests to you.
WPML a few days ago apparently a major update to version 4.3 was done at WPML Multilingual CMS and also updates for Strings and Yoast SEO Multilingual.
A lot of users had problems, especially users with the Wow Shop and the WMPL support seems to be very stressed right now, I feel really sorry for them. Apparently the update wasn’t tested well enough.
Meanwhile there is a Hot Fix 4.3.1 which doesn’t solve all problems.
For me it was mainly the update of the Yoast SEO Multilingual that produced the 404 Errors. I deactivated it now. More info here.
https://wpml.org/errata/yoast-seo-multilingual-causes-404-on-secondary-languages/
Greetings and a nice weekend – Mark
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