Description of problem:
SELinux is preventing postgrey from 'read' accesses on the file unix.

*****  Plugin catchall (100. confidence) suggests   **************************

If you believe that postgrey should be allowed read access on the unix file by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c 'postgrey' --raw | audit2allow -M my-postgrey
# semodule -X 300 -i my-postgrey.pp

Additional Information:
Source Context                system_u:system_r:postgrey_t:s0
Target Context                system_u:object_r:proc_net_t:s0
Target Objects                unix [ file ]
Source                        postgrey
Source Path                   postgrey
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           
Target RPM Packages           
SELinux Policy RPM            selinux-policy-targeted-3.14.6-35.fc33.noarch
Local Policy RPM              selinux-policy-targeted-3.14.6-35.fc33.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 5.11.7-200.fc33.x86_64 #1 SMP Wed
                              Mar 17 18:55:20 UTC 2021 x86_64 x86_64
Alert Count                   2
First Seen                    2021-03-22 08:25:14 EDT
Last Seen                     2021-03-22 08:25:19 EDT
Local ID                      4a546b93-3650-4d74-b609-a58bdabe6b07

Raw Audit Messages
type=AVC msg=audit(1616415919.456:635): avc:  denied  { read } for  pid=1523 comm="postgrey" name="unix" dev="proc" ino=4026532059 scontext=system_u:system_r:postgrey_t:s0 tcontext=system_u:object_r:proc_net_t:s0 tclass=file permissive=0


Hash: postgrey,postgrey_t,proc_net_t,file,read

Version-Release number of selected component:
selinux-policy-targeted-3.14.6-35.fc33.noarch

Additional info:
component:      selinux-policy
reporter:       libreport-2.14.0
hashmarkername: setroubleshoot
kernel:         5.11.7-200.fc33.x86_64
type:           libreport

Potential duplicate: bug 1848559