Warnings from Moesia Teamplate

Hi Support-Team,

Following warnings occur, when updating my homepage. I inserted a link to a picture.
What ist to be done?

Regards,
Knut

Warning : call_user_func_array() expects parameter 1 to be a valid callback, class ‘Moesia_Action’ does not have a method ‘flush_widget_cache’ in /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-includes/class-wp-hook.php on line 305

Warning : call_user_func_array() expects parameter 1 to be a valid callback, class ‘Moesia_Action’ does not have a method ‘flush_widget_cache’ in /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-includes/class-wp-hook.php on line 305

Warning : call_user_func_array() expects parameter 1 to be a valid callback, class ‘Moesia_Action’ does not have a method ‘flush_widget_cache’ in /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-includes/class-wp-hook.php on line 305

Warning : call_user_func_array() expects parameter 1 to be a valid callback, class ‘Moesia_Action’ does not have a method ‘flush_widget_cache’ in /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-includes/class-wp-hook.php on line 305

Warning : Cannot modify header information - headers already sent by (output started at /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-includes/class-wp-hook.php:305) in /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-admin/post.php on line 231

Warning : Cannot modify header information - headers already sent by (output started at /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-includes/class-wp-hook.php:305) in /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-includes/pluggable.php on line 1340

Warning : Cannot modify header information - headers already sent by (output started at /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-includes/class-wp-hook.php:305) in /homepages/14/d71175075/htdocs/DenkerpriseStaging/wp-includes/pluggable.php on line 1343

Hi,

Thank you for contacting us. I am happy to help with your problems.

Can you let me know which version of WordPress you’re running? Is it the latest?

Maybe this issue is related to a specific version of WordPress. Meanwhile, can you try disabling WP DEBUG mode? Debugging in WordPress | WordPress.org

Regards,
Kharis
aThemes Support