There is a bug in Bitsend regarding masternode outputs and remote starting of masternodes.
If you have "mnconflock=1" in your bitsend.conf, masternode outputs are locked so that you can't spend them inadvertently, which is good. Unfortunately, this also prevents you from starting your masternode remotely, because the wallet can't find the 25000 BSD VIN anymore, which can be seen as a bug.
So, to start your masternode remotely, temporarily set mnconflock to 0 in your bitsend.conf, restart wallet and start your masternode.
I didn't have the mnconflock linein my conf file, but so I added mnconflock=0, and restarted the wallet. I still can't allocate VIN and the 25k balance is still locked in the Inputs section. How do I unlock it?
Strange. Are you sure you changed the right bitsend.conf? Also make sure that the wallet is not started with the command line parameter "-mnconflock".
You can unlock an input manually in the wallet: In Coin Control, select the locked transaction with right mouse button and unlock it via popup menue. This is a temporary solution until next wallet start.