If the exporter remains locked for over an hour, then most probably the exporter script has encountered a fatal error that halted the script.

In this scenario you need to search from all your error logs for possible clue.

If you think that you have resolved it, or just want to re-try again, then you can just unlock the exporter according to the instructions on the screenshot.

It is not possible to unlock an expoter if it has been locked for less than one hour. This is a safety feature accidentally not to unlock the exporters, which are actually running.