Is the loss of all a non-trained trader's money in the currency exchange a punishment or a trial from Allah?

No one can definitively state whether what befell him is a punishment or a trial for elevating his status, because that pertains to the unseen. A believer must exercise patience, seek forgiveness, and repent. Allah may test His servants to elevate their ranks and multiply their good deeds, or due to sins and transgressions. Some scholars have mentioned signs to differentiate between punishment and trial: punishment is accompanied by impatience, panic, and complaint, whereas a trial for expiating sins is accompanied by beautiful patience, and a trial for elevating status is accompanied by contentment and inner peace.