Warning: Trying to access array offset on null in /usr/www/users/iconomiwed/wp-includes/block-template.php on line 104

Fatal error: Uncaught ValueError: Path cannot be empty in /usr/www/users/iconomiwed/wp-includes/block-template.php:104
Stack trace:
#0 /usr/www/users/iconomiwed/wp-includes/block-template.php(104): file_get_contents('')
#1 /usr/www/users/iconomiwed/wp-includes/template.php(66): locate_block_template('/usr/www/users/...', 'single', Array)
#2 /usr/www/users/iconomiwed/wp-includes/template.php(571): get_query_template('single', Array)
#3 /usr/www/users/iconomiwed/wp-includes/template-loader.php(81): get_single_template()
#4 /usr/www/users/iconomiwed/wp-blog-header.php(19): require_once('/usr/www/users/...')
#5 /usr/www/users/iconomiwed/index.php(17): require('/usr/www/users/...')
#6 {main}
  thrown in /usr/www/users/iconomiwed/wp-includes/block-template.php on line 104