Try using the following command: repquota -av or repquota -av |grep clamav
See if ClamAV has limited quota or not if it does you can then use the following command
"edquota clamav"
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It could also be that /usr/share/clamav has wrong permissions. Check who it is owned by and if it's owned by another user then change ownership to "clamav"
DatabaseOwner in the freshclam.conf file should also be clamav