Thanks for reaching out, and thanks for choosing a WordPress theme by BoldGrid. I’m sorry to hear that you can’t log into your WordPress site.
I visited your site and I can see that there is an error, but right now it doesn’t look like debugging is enabled so it’s tough to speculate what might have gone wrong.
First, check your email account for an email from your website. Since WordPress 5.2, there is a recovery mode that you can use to get access back to your site if a plugin or theme has caused an error, and there will be a link to log into your site with the offending plugin or theme disabled.
We have a detailed tutorial on the next steps you can take to recover from a fatal error, including instructions on how to change the theme using your host’s Database Administration tool or using the command line via SSH.
If you’re still having trouble, can you let us know which theme you installed, and if possible enable WP_DEBUG_DISPLAY in your wp-config.php file so we can examine the error message?