Good afternoom

I have to change the web of a company that currently is using a free theme. I install this theme and WP Bakery Page and now, the old pages don't work. 

It's all the time trying to refresh, but nothing appears

Also I've tried to create a new page with a template, and it's not working. In backend it appears the structure, but in frontend it's in white

I send few screenshots

Thanks a lot for the help!