I have purchased a tool belt and an engineers vest several months ago, and was happily wearing them. When I recntly left my ship for a formal occasion I decided to take them off and leave them in my trunk in the cargo bay.
However I seem to be unable to put them back on (equip them) again.
Provided you aren't doing it wrong, it's known that there are a few issues with items at the moment, so this may be a side effect. However, it would help if you could describe exactly what you did and any error messages you received.