i cant convert a WPA / WPA2 pcap

[ZerBea]

and if you really need to clean up your cap file: tshark is your friend

for output format pcap (cap2hccapx understand this):
tshark -r raw.cap -R "(wlan.fc.type_subtype == 0x00 || wlan.fc.type_subtype == 0x02 || wlan.fc.type_subtype == 0x04 || wlan.fc.type_subtype == 0x05 || wlan.fc.type_subtype == 0x08 || eapol)" -2 -F pcap -w cleaned.pcap

or new pcapng format (hcxpcaptool understand this):
tshark -r raw.cap -R "(wlan.fc.type_subtype == 0x00 || wlan.fc.type_subtype == 0x02 || wlan.fc.type_subtype == 0x04 || wlan.fc.type_subtype == 0x05 || wlan.fc.type_subtype == 0x08 || eapol)" -2 -F pcapng -w cleaned.pcapng