Fatal Error on Activation

My photo feed stopped working and I noticed that the Feed Them plugin was de-activated. When I tried to activate it, I got this error:

Parse error: syntax error, unexpected T_STRING in /var/www/vhosts/site/httpdocs/wp-content/plugins/feed-them-social/feed-them.php on line 51

I uninstalled and re-installed the plugin and the same thing happens.

https://ww.wp.xz.cn/plugins/feed-them-social/