Add new theme not showing any theme

Hi guys,
My wordpress is not showing any themes exceot the default ones (3 themes). When I click on “add new” it gives me an error. The error text is:
“An unexpected error occurred. Something may be wrong with www.remarpro.com or this server’s configuration. If you continue to have problems, please try the support forums.”

That is why I am here with you. Anybody know hiw to solve it?