Thank you very much...!
With your guide, I've detected that the problem was ioncube compatibility used in a local (Cuenta Digital -Argentina) payment gateway that is not supported by PHP 7.0 version.
I've downgraded PHP version to 5.6 and every works fine now
I really appreciate your quick assistance !
I'm sorry. Just tested and found new issue, customers can't see their invoices too .From Client area we get same error message (Oops... )
I'm thinking that i will roll-back to version previous to 7.5 to get every working fine again...
Thank you for your reply.
I've updated to 7.5.1 and it was solved, but now i get same message from "config gateways"
Oops!
Something went wrong and we couldn't process your request.
Please go back to the previous page and try again.
At this time can't see if everything is running properly !
Can you help me please ?