diff --git a/apps/api/src/services/prisma/prisma.service.ts b/apps/api/src/services/prisma/prisma.service.ts
index fcf7c6e5ea..ece0fd8140 100644
--- a/apps/api/src/services/prisma/prisma.service.ts
+++ b/apps/api/src/services/prisma/prisma.service.ts
@@ -25,7 +25,7 @@ export class PrismaService
 
     try {
       customLogLevels = JSON.parse(
-        configService.get<string>('LOG_LEVELS')
+        configService.get<string>('LOG_LEVELS') ?? ''
       ) as LogLevel[];
     } catch {}
 
diff --git a/apps/api/src/services/property/property.service.ts b/apps/api/src/services/property/property.service.ts
index 6d8130bbc2..4435fd220d 100644
--- a/apps/api/src/services/property/property.service.ts
+++ b/apps/api/src/services/property/property.service.ts
@@ -16,8 +16,8 @@ import { PropertyValue } from './interfaces/interfaces';
 export class PropertyService {
   private static readonly CACHE_TTL = ms('1 minute');
 
-  private cachedProperties: Promise<Property[]>;
-  private cachedPropertiesExpiresAt: Date;
+  private cachedProperties?: Promise<Property[]>;
+  private cachedPropertiesExpiresAt?: Date;
 
   public constructor(private readonly prismaService: PrismaService) {}
 
@@ -91,6 +91,7 @@ export class PropertyService {
 
     if (
       this.cachedProperties &&
+      this.cachedPropertiesExpiresAt &&
       isBefore(new Date(), this.cachedPropertiesExpiresAt)
     ) {
       return this.cachedProperties;
diff --git a/apps/api/src/services/redis-cache/redis-cache.service.mock.ts b/apps/api/src/services/redis-cache/redis-cache.service.mock.ts
index 78ecda1c9d..77ee164a6f 100644
--- a/apps/api/src/services/redis-cache/redis-cache.service.mock.ts
+++ b/apps/api/src/services/redis-cache/redis-cache.service.mock.ts
@@ -3,8 +3,8 @@ import { PerformanceCalculationType } from '@ghostfolio/common/types/performance
 
 export const RedisCacheServiceMock = {
   cache: new Map<string, string>(),
-  get: (key: string): Promise<string> => {
-    const value = RedisCacheServiceMock.cache.get(key) || null;
+  get: (key: string): Promise<string | undefined> => {
+    const value = RedisCacheServiceMock.cache.get(key);
 
     return Promise.resolve(value);
   },
@@ -19,7 +19,7 @@ export const RedisCacheServiceMock = {
   }): string => {
     const filtersHash = filters?.length;
 
-    return `portfolio-snapshot-${userId}-${calculationType}${filtersHash > 0 ? `-${filtersHash}` : ''}`;
+    return `portfolio-snapshot-${userId}-${calculationType}${filtersHash && filtersHash > 0 ? `-${filtersHash}` : ''}`;
   },
   reset: () => {
     RedisCacheServiceMock.cache.clear();
diff --git a/apps/api/src/services/redis-cache/redis-cache.service.ts b/apps/api/src/services/redis-cache/redis-cache.service.ts
index 857d96e945..5e64f5a635 100644
--- a/apps/api/src/services/redis-cache/redis-cache.service.ts
+++ b/apps/api/src/services/redis-cache/redis-cache.service.ts
@@ -33,7 +33,7 @@ export class RedisCacheService {
     });
   }
 
-  public async get(key: string): Promise<string> {
+  public async get(key: string): Promise<string | undefined> {
     return this.cache.get(key);
   }
 
@@ -42,9 +42,11 @@ export class RedisCacheService {
     const prefix = aPrefix;
 
     try {
-      for await (const [key] of this.client.iterator({})) {
-        if ((prefix && key.startsWith(prefix)) || !prefix) {
-          keys.push(key);
+      if (this.client.iterator) {
+        for await (const [key] of this.client.iterator({})) {
+          if ((prefix && key.startsWith(prefix)) || !prefix) {
+            keys.push(key);
+          }
         }
       }
     } catch {}
@@ -63,7 +65,7 @@ export class RedisCacheService {
   }) {
     let portfolioSnapshotKey = `${this.getPortfolioSnapshotKeyPrefix({ userId })}-${calculationType}`;
 
-    if (filters?.length > 0) {
+    if (filters && filters.length > 0) {
       const filtersHash = createHash('sha256')
         .update(JSON.stringify(filters))
         .digest('hex');