This thread is resolved. Here is a description of the problem and solution.
Problem:
Website is constantly crashing. Always getting 500 or 503 error.
WP memory limit is set to 256mb and wp memory max limit is also set to 256mb
Solution:
After further verification, it is too soon to confirm that WPML is the cause of the performance issue,
Suggested the user to:
1- Enable WP debug log in order to see if there are any obvious error logs
2- To disable all plugins but WPML and then enable them one by one to see which plugin is conflicting with WPML
Relevant Documentation:
This is the technical support forum for WPML - the multilingual WordPress plugin.
Everyone can read, but only WPML clients can post here. WPML team is replying on the forum 6 days per week, 22 hours per day.