mymonero-app-js: Can't spend coinbase txs

I have stagenet wallet (seed below) which has only few coinbase txs (no other txs present). I can’t spend anything from this wallet. The mymonero-app-js constructs txs and submits it to daemon, but demon rejects it with the message:

2018-10-25 06:07:34.847	[RPC0]	WARN 	daemon.rpc	src/rpc/core_rpc_server.cpp:728	[on_send_raw_tx]: tx verification failed: invalid input

Not really sure if this is problem with mymonero-app-js, but before I started testing it with openmonero’s backend, I could spend coninbase txs. Thus I think that this is some problem with mymonero-app-js and its new codebase.

Would you mind checking if you can spend coinbase txs?

Stagenet wallet seed:

peaches purged gossip either gyrate organs asked ability autumn inexact coffee rays avidly fountain foxes wrist goldfish masterful anecdote sulking masterful science beyond coffee coffee