You could use
gpg -c file.txt, since GPG supports encrypting a file with a passphrase and symmetric encryption.
The issue with openssl is most likely either a version mismatch or you're simply not using the right command. You could pull down the most recent code for openssl command line utility off github and compile it from source on all the computers, so they all have the same version.
You could also try manually specifying the Key Derivation Function parameters for openssl, for example:
openssl enc -aes-256-cbc -pbkdf2 -salt -iter 100000 -in archive.tar.gz -out encrypted.tar.gz.ossl, which might resolve the issue without compiling from source (I'm not sure, but a newer version might use a more secure KDF by default, which causes decryption errors unless you manually specify the proper arguments)