Error message displayed at top of site

Last night I ran the latest update to wordpress and after running it there is now an error message displayed. The error message comes at the top of the screen on every page of the website – the site itself seems to function fine but displays this error message:

Warning: ftp_fget() expects parameter 1 to be resource, null given in /home/smhailsham/LSWT68X5/htdocs/wp-admin/includes/class-wp-filesystem-ftpext.php on line 143

When logging in as administrator there are 5 error messages displayed. I can see that this relates to a file ‘ class-wp-filesystem-ftpext.php ‘ and I was able to download a copy of this through the control panel. I used a program called notepad++ to open and read the file and line 143 reads:

if ( ! ftp_fget( $this->link, $temp, $file, FTP_BINARY ) )

I found a definition of the function ftp_fget() here https://www.php.net/manual/en/function.ftp-fget.php. The first parameter in this formula should be the resource for which the formula above defines as $this->link.

This is the extent of my investigation and I don’t know what to do to resolve this. When logging in as administrator to the website there are 5 errors as follows that all relate to this same file:

Warning: ftp_fget() expects parameter 1 to be resource, null given in /home/smhailsham/LSWT68X5/htdocs/wp-admin/includes/class-wp-filesystem-ftpext.php on line 143

Warning: ftp_nlist() expects parameter 1 to be resource, null given in /home/smhailsham/LSWT68X5/htdocs/wp-admin/includes/class-wp-filesystem-ftpext.php on line 402

Warning: ftp_pwd() expects parameter 1 to be resource, null given in /home/smhailsham/LSWT68X5/htdocs/wp-admin/includes/class-wp-filesystem-ftpext.php on line 226

Warning: ftp_pwd() expects parameter 1 to be resource, null given in /home/smhailsham/LSWT68X5/htdocs/wp-admin/includes/class-wp-filesystem-ftpext.php on line 226

Warning: ftp_pwd() expects parameter 1 to be resource, null given in /home/smhailsham/LSWT68X5/htdocs/wp-admin/includes/class-wp-filesystem-ftpext.php on line 681

All of these formulas contain the phrase $this->link which seems to be the root of the problem.

Whilst I know a fair bit about computers, websites are a bit of a mystery and I’ve been rather ‘blaging it’ trying to look after and update our website. Any adfvice would be welcomed.

I tried deactivating all plugins but this had no effect. We use the Native Church Child theme.

Thanks

The page I need help with: [log in to see the link]