Without any further details, I try to guess: Are your base URLs of the magento installation correct?
You could use the following commands to get the current values:
SELECT * FROM core_config_data WHERE `path` LIKE '%web/unsecure/base_url%';
SELECT * FROM core_config_data WHERE `path` LIKE '%web/secure/base_url%';
If not, you have to adjust them either directly within the database or via the console according to the official documentation on store cli commands (
General migration procedure
After loading the database dump and extracting your backup, you have to set the correct database credentials in
app/etc/env.php within the installation directory.
Then, you should check the database for the following two values in
Update the filesystem ownership and permissions: Please refer to the official tutorial on filesystem ownership and the official tutorial on permissions on production and development mode.
If you want to run this installation in production, run the
magento deploy:mode production command (as magento user/magento file system owner) to delete and regenerate caches, etc. Otherwise clear them.
Last but not least: Check the Cronjobs (if you used them on your old machine.
Please refer to Khoa TruongDinh's answer to a similar question for further details.