Fatal error while activating

I just created a new installation. I have only 2 plugins: Siteground Optimizer and Gutenberg.

By installing and activating Stackable, I get this error on the plugins page:

Parse error: syntax error, unexpected '*', expecting ',' or ';' in /home/folder/public_html/site.domain/subdomainfolder/wp-content/plugins/stackable-ultimate-gutenberg-blocks/src/welcome/notification-rate.php on line 21

• This topic was modified 5 years, 12 months ago by Christian Rodríguez.