diff --git a/src/CommonLib/LdapUtils.cs b/src/CommonLib/LdapUtils.cs
index 14612da12..c560d4b6d 100644
--- a/src/CommonLib/LdapUtils.cs
+++ b/src/CommonLib/LdapUtils.cs
@@ -386,6 +386,8 @@ public IAsyncEnumerable<LdapResult<IDirectoryObject>> PagedQuery(LdapQueryParame
 
         private async Task<(bool Success, string DomainName)> ConvertDomainSidToDomainNameFromLdap(string domainSid) {
             if (!GetDomain(out var domain) || domain?.Name == null) {
+                // fix: BED-6026 adding the domainSid to _unresolvablePrincipals cache to prevent repeated resolving
+                _unresolvablePrincipals.Add(domainSid);
                 return (false, string.Empty);
             }