There are several possible reasons for that. If this worked before, a re-boot of your system would be a first try. If it didn't work before I would check (change) the cables and the settings.
Miniprog 3? Did you connect and set parameters correctly for SWD (Tools->Options->Programming/Debug->Miniprog3)
Most often this happens if your device is not powered and connectivity issues. Please check your power supply and cables. Also make sure that no other application(like USB-I2C bridge) does not use Miniprog3.
I too have faced this a number of times.As U2 said,it could be that another application is using it.
But the solution that works best for me is to open a new instance of PSoC Programmer,and program the hex file using that,given that all connections are okay.
Yes,I know that both use the same underlying code,Creator uses its COM object,but still...Programmer has yet to fail me when Creator has.
I've realised that whenever i try to program the PSoC chip on the development board without my target board powerer(i.e. my robot being controlled) i register this problem and whenever i switch the power on to my target application the port acquire executes successful.
Thanks for the efforts. Everything is working well now and i'm not having any problems now
Device not being powered was the root cause for the Port Acquire failure.
Note that you can power the PSoC Device using Miniprog3, but if there are other high current consuming components on your robot which share the supply voltage with PSoC, using this as a supply is not advisable.