Mask Processor Wordlist

[Alean]

So ive been digging around to find a way to crack this handshake cap file i have. I know the pw is only uppercase letters and numbers, so i thought i'll try to make a wordlist like that with mask, but after a test run with a file that only contained 4 chars aircrack gave me the msg that the file i created is not in a supported format? O.o even tho it seems to be a regular txt so idk if thats normal or if i made a mistake somewhere along the way. I should point out that i do not have a CUDA compatibile graphic card so cant use hashcat at least thats what i think Either way thanks for any help in advance.