diff --git a/CHANGELOG.md b/CHANGELOG.md
index d2aa682b30..1a21ab9a4b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Resolved an exception in the `GET api/v1/portfolio/holding/:dataSource/:symbol` endpoint for cash positions
+- Improved the error handling in the access endpoints (`POST` and `PUT`) to return `400 Bad Request` when granting access to a non-existent user
 
 ## 3.31.0 - 2026-07-20
 
diff --git a/apps/api/src/app/access/access.controller.ts b/apps/api/src/app/access/access.controller.ts
index 35b1d485b0..d692f358df 100644
--- a/apps/api/src/app/access/access.controller.ts
+++ b/apps/api/src/app/access/access.controller.ts
@@ -87,7 +87,7 @@ export class AccessController {
     }
 
     try {
-      return this.accessService.createAccess({
+      return await this.accessService.createAccess({
         alias: data.alias || undefined,
         granteeUser: data.granteeUserId
           ? { connect: { id: data.granteeUserId } }
@@ -155,7 +155,7 @@ export class AccessController {
     }
 
     try {
-      return this.accessService.updateAccess({
+      return await this.accessService.updateAccess({
         data: {
           alias: data.alias,
           granteeUser: data.granteeUserId
diff --git a/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts b/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
index cee94f0208..c1e795c4af 100644
--- a/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
+++ b/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
@@ -51,6 +51,8 @@ import {
   format,
   isAfter,
   isBefore,
+  isFuture,
+  isPast,
   isWithinInterval,
   min,
   startOfDay,
@@ -134,7 +136,7 @@ export abstract class PortfolioCalculator {
             dateOfFirstActivity = date;
           }
 
-          if (isAfter(date, new Date())) {
+          if (isFuture(date)) {
             // Adapt date to today if activity is in future (e.g. liability)
             // to include it in the interval
             date = endOfDay(new Date());
@@ -1113,7 +1115,7 @@ export abstract class PortfolioCalculator {
         portfolioSnapshot
       );
 
-      if (isAfter(new Date(), new Date(expiration))) {
+      if (isPast(new Date(expiration))) {
         isCachedPortfolioSnapshotExpired = true;
       }
     } catch {}
diff --git a/apps/api/src/services/benchmark/benchmark.service.ts b/apps/api/src/services/benchmark/benchmark.service.ts
index 99ceaf21ef..affb0da08f 100644
--- a/apps/api/src/services/benchmark/benchmark.service.ts
+++ b/apps/api/src/services/benchmark/benchmark.service.ts
@@ -23,7 +23,7 @@ import { BenchmarkTrend } from '@ghostfolio/common/types';
 import { Injectable, Logger } from '@nestjs/common';
 import { SymbolProfile } from '@prisma/client';
 import { Big } from 'big.js';
-import { addHours, isAfter, subDays } from 'date-fns';
+import { addHours, isPast, subDays } from 'date-fns';
 import { round, uniqBy } from 'lodash';
 import ms from 'ms';
 
@@ -94,7 +94,7 @@ export class BenchmarkService {
 
         this.logger.debug('Fetched benchmarks from cache');
 
-        if (isAfter(new Date(), new Date(expiration))) {
+        if (isPast(new Date(expiration))) {
           this.calculateAndCacheBenchmarks({
             enableSharing
           });
diff --git a/apps/client/src/app/components/investment-chart/investment-chart.component.ts b/apps/client/src/app/components/investment-chart/investment-chart.component.ts
index dc3152f120..3aa65b9983 100644
--- a/apps/client/src/app/components/investment-chart/investment-chart.component.ts
+++ b/apps/client/src/app/components/investment-chart/investment-chart.component.ts
@@ -41,7 +41,7 @@ import {
 } from 'chart.js';
 import 'chartjs-adapter-date-fns';
 import { type AnnotationOptions } from 'chartjs-plugin-annotation';
-import { isAfter } from 'date-fns';
+import { isFuture } from 'date-fns';
 import { NgxSkeletonLoaderModule } from 'ngx-skeleton-loader';
 
 @Component({
@@ -311,6 +311,6 @@ export class GfInvestmentChartComponent implements OnChanges, OnDestroy {
       return undefined;
     }
 
-    return isAfter(new Date(xValue), new Date()) ? aValue : undefined;
+    return isFuture(new Date(xValue)) ? aValue : undefined;
   }
 }