question about sgx_sign

I use the two-step signing process to sign my enclave, the makefile is :
$(Signed_Enclave_Name): $(Enclave_Name)
@$(SGX_ENCLAVE_SIGNER) gendata -enclave $(Enclave_Name) -config $(Enclave_Config_File) -out enclave_hash.hex
$(SGX_ENCLAVE_SIGNER) catsig -enclave enclave.so -config $(Enclave_Config_File) -out $@ -key Enclave/public_key.pem -sig signature.hex -unsigned enclave_hash.hex
@echo "SIGN => $@"
but there is an error:

0
0
0x40000
0x100000
10
1

0
0
0xFFFFFFFF

tcs_num 10, tcs_max_num 10, tcs_min_pool 1
The required memory is 4485120B.
Succeed.
/home/ubuntu-sqq/Graphene/graphene_SGX/sgxsdk/bin/x64/sgx_sign catsig -enclave enclave.so -config Enclave/Enclave.config.xml -out enclave.signed.so -key Enclave/public_key.pem -sig signature.hex -unsigned enclave_hash.hex

0
0
0x40000
0x100000
10
1

0
0
0xFFFFFFFF

tcs_num 10, tcs_max_num 10, tcs_min_pool 1
The required memory is 4485120B.
Failed to open file "signature.hex".
The signature file "signature.hex" is not correct.
Error happened while signing the enclave.
Makefile:250: recipe for target 'enclave.signed.so' failed
make: *** [enclave.signed.so] Error 255

what is wrong and what should I do?
Thanks!