The dirmngr continuously restarts the lookup if the keyserver returns 503 error.
$ dirmngr
dirmngr[16930]: No ldapserver file at: '/home/test/.gnupg/dirmngr_ldapservers.conf'
dirmngr[16930.0]: permanently loaded certificates: 132
dirmngr[16930.0]: runtime cached certificates: 0
dirmngr[16930.0]: trusted certificates: 132 (131,0,0,1)
- Home: /home/test/.gnupg
- Config: [none]
OK Dirmngr 2.2.16 at your service
KEYSERVER --clear hkps://keys.fedoraproject.org:443
OK
KS_GET -- 0x8657980D9AB51E50
dirmngr[16930.0]: resolve_dns_addr for 'keys.fedoraproject.org': 'keys.fedoraproject.org' [already known]
dirmngr[16930.0]: resolve_dns_addr for 'keys.fedoraproject.org': 'keys.fedoraproject.org' [already known]
dirmngr[16930.0]: number of system provided CAs: 152
dirmngr[16930.0]: error accessing 'https://keys.fedoraproject.org:443/pks/lookup?op=get&options=mr&search=0x8657980D9AB51E50': http status 503
S PROGRESS tick ? 0 0
dirmngr[16930.0]: selecting a different host due to a 503 (Service Unavailable)
dirmngr[16930.0]: error accessing 'https://keys.fedoraproject.org:443/pks/lookup?op=get&options=mr&search=0x8657980D9AB51E50': http status 503
S PROGRESS tick ? 0 0
dirmngr[16930.0]: selecting a different host due to a 503 (Service Unavailable)
dirmngr[16930.0]: error accessing 'https://keys.fedoraproject.org:443/pks/lookup?op=get&options=mr&search=0x8657980D9AB51E50': http status 503
dirmngr[16930.0]: selecting a different host due to a 503 (Service Unavailable)
dirmngr[16930.0]: error accessing 'https://keys.fedoraproject.org:443/pks/lookup?op=get&options=mr&search=0x8657980D9AB51E50': http status 503
S PROGRESS tick ? 0 0
dirmngr[16930.0]: selecting a different host due to a 503 (Service Unavailable)
dirmngr[16930.0]: error accessing 'https://keys.fedoraproject.org:443/pks/lookup?op=get&options=mr&search=0x8657980D9AB51E50': http status 503
dirmngr[16930.0]: selecting a different host due to a 503 (Service Unavailable)
dirmngr[16930.0]: error accessing 'https://keys.fedoraproject.org:443/pks/lookup?op=get&options=mr&search=0x8657980D9AB51E50': http status 503
S PROGRESS tick ? 0 0
dirmngr[16930.0]: selecting a different host due to a 503 (Service Unavailable)
dirmngr[16930.0]: error accessing 'https://keys.fedoraproject.org:443/pks/lookup?op=get&options=mr&search=0x8657980D9AB51E50': http status 503
^C