Warning: Invalid argument supplied for foreach

I’m facing a problem when I try to access my login page on:
The following error appears:

Warning: Invalid argument supplied for foreach() in /home/aceis910/public_html/wp-content/themes/sydney/plugins/class-tgm-plugin-activation.php on line 1926

Warning: Cannot modify header information – headers already sent by (output started at /home/aceis910/public_html/wp-content/themes/sydney/plugins/class-tgm-plugin-activation.php:1926) in /home/aceis910/public_html/wp-includes/pluggable.php on line 1219

I have no idea how it get there, because it’s been two weeks I don’t access my website and I haven’t made any change on it.
I’m not good with htlm or php codes, so I have no idea what to do about it.

Can anyone help me please?

Hello there,

Really sorry for the inconvenience, we’re working to fix this issue and it’ll be available immediately as the new version coming. At this time, please allow me to access your site’s FTP, so I can do direct fix. Share the valid login access to FTP or cPanel of your site to my email at kharisblank@gmail.com. Mention the link to this topic in your message body to signal it’s a followup from support forum.