The input is not a valid Base-64 string as it contains a non-base 64 character

[Ppsoft1991]

Hello, when I used this tool for brute forcing, I noticed that after 48 bits, the characters started to repeat, indicating that the key length is 48. Because the version number was leaked from the upload interface, I didn’t need to brute force the version. I used the tool
python3 dp_cryptomg.py -l 48 xxx.com -s -k key -d -v version
to obtain the login address, but I received an
Error Message:The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters. in the response. Could you please provide some assistance?