Can't create Client SSL profile with self signed ECC certificate.

You can't have just an ECC-based cert in the ClientSSL profile - you need to have at least one traditional RSA key/cert defined in the profile as well (e.g. it will work with 2 sets of certs and keys).

For more details see SOL15062 'Associating multiple SSL certificate/key pair types with an SSL profile' https://support.f5.com/kb/en-us/solutions/public/15000/000/sol15062.html