No crank no start on 2001 525i

[cBryan024]

Just got done en engine swap bc last one took a dump right before 200k miles, swapped a 130k mile one in with a whole rebuild kit, when trying to crank it the solenoid clicks but not cranks. Reverse lights were on so we disconnected the reverse switch and it cranked once and the battery died so we charge it up but now it’s back to before we disconnected the switch, could it be the ecu reset itself? The car was a manual swap by the previous owner so maybe th car thinks it’s in gear? Let me know what you guys think!

[cBryan024]

Update: it cranks over now, I unlocked the car with the key manually and then cranked it and it cranked right up!