apt works just fine with those settings and repository:
Reading package lists... Done
W: GPG error: http://mirror.fuel-infra.org mos7.0-holdback Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CA2B20483E301371
W: GPG error: http://mirror.fuel-infra.org mos7.0-security Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CA2B20483E301371
W: GPG error: http://mirror.fuel-infra.org mos7.0-updates Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CA2B20483E301371
W: GPG error: http://mirror.fuel-infra.org mos7.0 Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CA2B20483E301371
apt works just fine with those settings and repository:
Reading package lists... Done mirror. fuel-infra. org mos7.0-holdback Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CA2B20483E301371 mirror. fuel-infra. org mos7.0-security Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CA2B20483E301371 mirror. fuel-infra. org mos7.0-updates Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CA2B20483E301371 mirror. fuel-infra. org mos7.0 Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CA2B20483E301371
W: GPG error: http://
W: GPG error: http://
W: GPG error: http://
W: GPG error: http://