Just got a brand new shiney Huawei P20 Pro phone.

Just got a brand new shiney Huawei P20 Pro phone. Quite a good beast, but when I try to debug programmes with Rad/Delphi, it compiles and links the programme, copies it to the phone, starts it running, then sits on the Delphi screen with the "Run" window. Nothing happens. When I press "Cancel", I get the message "Cannot start gdbserver on port 62311 (or whatever - I can't remember) - port already in use.
Any ideas about how to get gdbserver running happily again please?