Thank you for posting in our forum.
We understand your SSD went into some kind of frozen state and it was not accepting your password. This may be caused by either the drive itself or the computer BIOS; however, it is really hard to tell according to the scenario presented.
Our guess is that the drive could have been in a secure lock state and only after a power cycle or a restart of the whole system it went back to normal state.
If by any chance this happens again, we suggest you to try to unplug the cables while the system is on (In case the drive is SATA form factor) and try again.
In case you need further assistance, you can always provide us the logs from the drive, using the Intel® Solid State Drive Toolbox.
We are following up and we would like to know if you need anything else about this thread?
We will be waiting for your response.