Import Database 0%

Good morning, I have been using this fantastic plugin for many years but I am experiencing a very serious problem during file import on at least three sites that I manage with different hostings. I use the unlimited version and the plugin is version: Version 2.54. I’ll explain what happens. Once I export the file and import it, for example, onto another site, it continues correctly up to the first phase, but then after clicking on proceed to restore everything, it stops at 0% on the database and the site is not more accessible. What is going on? Thank you