VPN tunnel between SCALANCE M87x and SINEMA RC Server   
5.4 Configuring a remote connection on the M87x 
  SCALANCE M-800 Getting Started 
198  Getting Started, 06/2015, C79000-G8976-C337-04 
The certificates are loaded. With "Security" > "Certificates", you can display the certificates. 
The loaded certificates must have the status "valid".