This thread is resolved. Here is a description of the problem and solution.
Problem: Fatal error: Uncaught exception 'InvalidArgumentException' with message 'element_id and type do not match for element_id
Solution: This kind of error is happening because of corrupt entry or misconfiguration in the Database. In this case element_type which has element_id 1387 of wp_icl_translations database table doesn't match tax_category of this entry in wp_posts database table.
Please try the following steps after a full site backup to fix the issue.
1) Go to your database using phpMyAdmin(or something similar)
2) Go to wp_icl_translations database table
3) Find entry with element_id:1387 and delete that row
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