Hi @dineva
The issue seems related to your server settings. First, could you please increase the max_vars variable as mentioned on this page: https://www.advancedcustomfields.com/resources/limit-number-fields/?
Second, from the error log you gave me, it seems related to mod_fcgid. To fix it, please check this thread: http://stackoverflow.com/questions/14488567/premature-end-of-script-headers-index-php-mod-fcgid-read-data-timeout-in-61-s. If you don’t know how to do it, kindly get in touch with your hosting provider instead.
Thanks 🙂
