We are encountering an issue when trying to upgrade polling from SNMPv2c to SNMPv3 on one of our FortiGate firewalls. We have verified the username, password, and encryption/hashing algorithm match (MD5 and AES256) and are using the same password for auth and priv. Below is a sanitized output of an snmpd debug on the FortiGate. Please let me know if there is any more information I can provide
2018-12-28 11:28:44 snmpd: <msg> 153 bytes 10.X.X.X:44488 -> 10.Y.Y.Y/10.Y.Y.Y:161 (itf 23.23)
2018-12-28 11:28:44 snmpd: snmp_v3_recv_parse(53): packet (153 left)
2018-12-28 11:28:44 snmpd: snmp_v3_recv_parse(): version: 3 (147 left)
2018-12-28 11:28:44 snmpd: snmp_v3_recv_parse(): msgGlobalData (131 left)
2018-12-28 11:28:44 snmpd: data [(14) (02 02 63 f2 02 02 05 dc 04 01 07 02 01 03 )(..c...........)]
2018-12-28 11:28:44 snmpd: snmp_v3_recv_parse(): msgFlags: 0x07
2018-12-28 11:28:44 snmpd: snmp_usm_recv_parse(): packet (131 left)
2018-12-28 11:28:44 snmpd: snmp_usm_recv_parse(): msgSecurityParameters: sz=72 left=57
2018-12-28 11:28:44 snmpd: snmp_usm_secparams_parse(): msgSecurityParameters: sz=70 left=0
2018-12-28 11:28:44 snmpd: data [(70) (04 15 80 00 30 44 04 46 47 31 4b 35 44 33 49 31 35 38 30 35 30 35 35 02 04 5a ad 43 5c 02 04 01 79 0b 45 04 09 49 54 65 61 6d 55 73 65 72 04 0c a0 cd 96 8e 32 c0 ff da 0c 20 e9 78 04 08 90 8e 96 ef c5 81 7f 17 )(....0D.FG1K5D3I15805055..Z.C\...y.E..ITeamUser......2.... .x..........)]
2018-12-28 11:28:44 snmpd: snmp_usm_secparams_parse(): msgUserName: UserName(24 left)
2018-12-28 11:28:44 snmpd: snmp_usm_scopedpdu_decrypt(): priv params (salt) :-
2018-12-28 11:28:44 snmpd: data [(8) (90 8e 96 ef c5 81 7f 17 )(........)]
2018-12-28 11:28:44 snmpd: snmp_usm_scopedpdu_decrypt(): encrypted scopedPDU :-
2018-12-28 11:28:44 snmpd: data [(55) (11 88 b9 73 96 06 43 42 ae 1a 43 51 66 31 79 f2 3f ff 7c 6f cd ba a6 a8 51 34 e8 c2 59 93 c3 c5 76 9a b5 c5 d4 f0 13 e8 3e 26 f7 2d 19 ed 64 53 65 cc 8a d9 1e 12 c3 )(...s..CB..CQf1y.?.|o....Q4..Y...v.......>&.-..dSe......)]
2018-12-28 11:28:44 snmpd: snmp_usm_scopedpdu_decrypt(): decrypted scopedPDU (55) :-
2018-12-28 11:28:44 snmpd: data [(55) (c2 98 f9 11 6a 2c e0 8a 01 3c 77 09 29 0e 9d 80 a2 ae 32 2b 38 ee a2 e0 de aa 5f ff 59 28 9c 83 d7 90 cc 72 f1 cc bc c5 1a de f6 1d 09 35 84 ba d4 f1 9f cd 5f 71 03 )(....j,...<w.).....2+8....._.Y(.....r.........5......_q.)]
2018-12-28 11:28:44 snmpd: _snmp_v3_recv(): v3 recv parse failed. errno=-48 (USM decryption error)
2018-12-28 11:28:44 snmpd: </msg> 0
