Very Slow website after migrating with Duplicator

Hello,
Yesterday we migrate for one subdomain to a main domain our website, but since then I have troubles entering and loading the page is very slow.We did the folowing:
– Deactivate all the plugins and activate one by one from teh Control Panel.
– Talked to the server provider ( and they say everything is working fine)
– Change the .htaacces and leave minumum to load…
Still the issue is there.
We are running the last version of WP.
Any help will be appreciatted.
Thank you so much in advance
Marcela