Open SAP Course Developing and Extending SAP Fiori Elements Apps - /dmo/cl_fe_travel_generator issue

Hi Experts,

I was following the open sap course Developing and Extending SAP Fiori Elements Apps, and couldn't use the class /dmo/cl_fe_travel_generator to generate the services and CDS.

I keep getting below error.

SAP Fiori elements exercise generator

-------------------------------------

PUT operation failed.

Class name:

CX_XCO_GEN_PUT_EXCEPTION

Source position:

Line 8 of EXECUTE in CL_XCO_GEN_O_PUT_ABSTRACT

Additional messages:

DEVC ZFE_TRAVELING_000000: Object R3TR DEVC ZFE_TRAVELING_000000 is already locked on transport request TRLK900438.

I have also tried deleting and creating the Trial Account Twice as mentioned in help , but still it won't budge. Has anyone encountered same issue? Any solutions to this?