Role Does Not exist post server reboot

Hi ,I have found that post server reboot , one of the user/role is missing
from the postgres database . Need some assistance like how it is possible.
If the server gets rebooted then how come the role is missing ?

2023-01-30 13:26:18.995 GMT epiemxb(at)postgres [14541] 10.94.234.138(61392)
[00000] LOG: LDAP login failed for user
"CN=EPIEMXB,OU=MFUSERS,OU=ELASUserAccounts,DC=elas,DC=local" on server
"elwacpa1.abc.local": Invalid credentials
2023-01-30 13:26:18.995 GMT epiemxb(at)postgres [14541] 10.94.234.138(61392)
[00000] DETAIL: LDAP diagnostics: 80090308: LdapErr: DSID-0C090447,
comment: AcceptSecurityContext error, data 52e, v3839
2023-01-30 13:26:18.995 GMT epiemxb(at)postgres [14541] 10.94.234.138(61392)
[28000] FATAL: LDAP authentication failed for user "epiemxb"
2023-01-30 13:26:18.995 GMT epiemxb(at)postgres [14541] 10.94.234.138(61392)
[28000] DETAIL: Connection matched pg_hba.conf line 100: "host all all
0.0.0.0/0 ldap ldapserver=elwacpa1.abc.local
ldapbasedn="OU=UserAccounts,DC=es,DC=local"
ldapbinddn="CN=mfadmin,OU=MFUSERS,OU=ELASUserAccounts,DC=elas,DC=local"
ldapbindpasswd=" ldapsearchattribute=sAMAccountName ldaptls=1"
2023-01-30 13:26:24.302 GMT epiemxb(at)postgres [14569] 10.94.234.138(61400)
[28000] FATAL: role "epiemxb" does not exist
2023-01-30 13:26:32.050 GMT epiemxb(at)postgres [14573] 10.94.234.138(61410)
[28000] FATAL: role "epiemxb" does not exist
2023-01-30 13:29:22.400 GMT epiemxb(at)postgres [15263] 10.94.234.138(61513)
[28000] FATAL: role "epiemxb" does not exist

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Thanks & Regards
Rakesh Nashine