It looks like the subject line you provided is likely encrypted or encoded (e.g., a simple cipher or keyboard shift). "fydyw nwdz st msryh flahh trd lhmha" resembles a substitution cipher (possibly Atbash or a shift like Caesar).
Once decoded, the message will reveal a filename and a command. That file contains the next stage of the operation. Download- fydyw nwdz st msryh flahh trd lhmha
The transmission above is not garbled. It’s a cipher. Your first task is to break it. It looks like the subject line you provided