Dedicated Server GDPR (for Trading Platform)

I have a query related to GDPR before purchasing a dedicated server from you, I would like to know some information;
one of the client is starting it's service in EU for Gold Trading Platform (live stocks) and massive transactions possible and according to new EU GDPR policy it's required to have an server in EU and the main thing is we are multi-national IT firm, and we will be accessing server for maintenance and management time to time so will this affect the policy and have any restriction like not to access server outside EU as there will be customers information and other related information will be stored including transactions possible, Please clarify on that if that's not allowed or any restriction or what case could it violate, Looking forward to hear back ASAP so we can setup server immediately

Thank You