Warning: Cannot modify header information

This error came back after I fixed it by reinstall fresh copy of enfold. Searching the forum I see others have this same issue with the masonry images. Please advise.

This comes up on top of home page.
Warning: session_start(): Cannot send session cookie – headers already sent by (output started at /home/content/p3pnexwpnas02_data03/98/2599098/html/wp-content/themes/enfold/framework/php/avia_shortcodes/shortcodes.php:1) in /home/content/p3pnexwpnas02_data03/98/2599098/html/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/masonry_entries.php on line 32

Warning: session_start(): Cannot send session cache limiter – headers already sent (output started at /home/content/p3pnexwpnas02_data03/98/2599098/html/wp-content/themes/enfold/framework/php/avia_shortcodes/shortcodes.php:1) in /home/content/p3pnexwpnas02_data03/98/2599098/html/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/masonry_entries.php on line 32

This comes up when you try to access the wp-amin.
Warning: Cannot modify header information – headers already sent by (output started at /home/content/p3pnexwpnas02_data03/98/2599098/html/wp-content/themes/enfold/framework/php/avia_shortcodes/shortcodes.php:1) in /home/content/p3pnexwpnas02_data03/98/2599098/html/wp-includes/pluggable.php on line 1207