diff --git a/.env b/.env
index 004bbdb7..d5d04b6a 100644
--- a/.env
+++ b/.env
@@ -21,3 +21,5 @@ LOG_LEVEL_CONSOLE=warn
 FRACTAL_RUNNER_BACKEND=local
 #WARNING_BANNER_PATH=/path/to/banner.txt
 ENABLE_INTERACTIVE_ATTRIBUTE_FILTERS=false
+
+BODY_SIZE_LIMIT=5000000
diff --git a/CHANGELOG.md b/CHANGELOG.md
index b6b44453..d57323ca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@
 * Used `FRACTAL_BACKEND_RUNNER=local` instead of `local_experimental` (\#713);
 * Moved job submission healthcheck page to user menu (\#713);
 * Fixed bug in task-groups deletion in admin page (\#713);
+* Fixed bug in task order modal drag and drop (\#713);
+* Added admin accounting page (\#713);
+* Implemented user impersonation (\#713);
+* Improved error handling in proxy functions and documented the usage of Svelte Kit `BODY_SIZE_LIMIT` environment variable (\#713);
 
 # 1.15.0
 
diff --git a/__tests__/AlertError.test.js b/__tests__/AlertError.test.js
index d674a0f8..f8c8e050 100644
--- a/__tests__/AlertError.test.js
+++ b/__tests__/AlertError.test.js
@@ -43,4 +43,9 @@ describe('AlertError class', () => {
 		);
 		expect(error.getSimpleValidationMessage('zarr_url')).eq('error message');
 	});
+
+	it('Extract field error', () => {
+		const error = new AlertError({ message: 'Payload Too Large' }, 413);
+		expect(error.getSimpleValidationMessage()).eq('Payload Too Large');
+	});
 });
diff --git a/docs/environment-variables.md b/docs/environment-variables.md
index 2abec190..4bbbeb3c 100644
--- a/docs/environment-variables.md
+++ b/docs/environment-variables.md
@@ -24,7 +24,8 @@ The following environment variables can be used to configure fractal-web.
 When running directly using `node` command these extra variables can also be configured:
 
 * `PORT`: specifies the port where Svelte server will run; the default value is 5173;
-* `ORIGIN` the URL where the app will be served (e.g. http://localhost:5173, or https://subdomain.example.org).
+* `ORIGIN` the URL where the app will be served (e.g. http://localhost:5173, or https://subdomain.example.org);
+* `BODY_SIZE_LIMIT`: the maximum request body size accepted in bytes; see [official SvelteKit documentation](https://svelte.dev/docs/kit/adapter-node#Environment-variables-BODY_SIZE_LIMIT).
 
 ## Common issues related to environment variables
 
diff --git a/docs/quickstart.md b/docs/quickstart.md
index 2fa8a9c8..b9274fc5 100644
--- a/docs/quickstart.md
+++ b/docs/quickstart.md
@@ -49,6 +49,7 @@ export AUTH_COOKIE_DOMAIN=
 
 export ORIGIN=http://localhost:5173
 export PORT=5173
+export BODY_SIZE_LIMIT=5000000
 
 export LOG_FILE=fractal-web.log
 # default values for logging levels (uncomment if needed)
diff --git a/src/lib/common/errors.js b/src/lib/common/errors.js
index d184a861..4a2710ed 100644
--- a/src/lib/common/errors.js
+++ b/src/lib/common/errors.js
@@ -89,6 +89,9 @@ export function extractErrorDetail(errorResponse) {
  * @returns {null | { loc: string[], msg: string } | string}
  */
 function getSimpleValidationMessage(reason, statusCode) {
+	if (typeof reason === 'object' && 'message' in reason && typeof reason.message === 'string') {
+		return reason.message;
+	}
 	if (!isValidationError(reason, statusCode)) {
 		return null;
 	}
diff --git a/src/routes/healthcheck/+page.svelte b/src/routes/healthcheck/+page.svelte
index 3e19c19e..1bcdf09c 100644
--- a/src/routes/healthcheck/+page.svelte
+++ b/src/routes/healthcheck/+page.svelte
@@ -228,7 +228,7 @@
 				{#if inProgress}
 					<span class="spinner-border spinner-border-sm" role="status" aria-hidden="true" />
 				{/if}
-				Test
+				Run test
 			</button>
 		</div>
 	</div>
diff --git a/src/routes/proxy.js b/src/routes/proxy.js
index f7b1ec57..5d1fc232 100644
--- a/src/routes/proxy.js
+++ b/src/routes/proxy.js
@@ -19,8 +19,7 @@ export function createGetProxy(path, forbiddenPaths = []) {
 				headers: filterHeaders(request.headers)
 			});
 		} catch (err) {
-			logger.debug(err);
-			throw err;
+			handleError(err);
 		}
 	};
 }
@@ -44,8 +43,7 @@ export function createPostProxy(path, forbiddenPaths = []) {
 				duplex: 'half'
 			});
 		} catch (err) {
-			logger.debug(err);
-			throw err;
+			handleError(err);
 		}
 	};
 }
@@ -68,8 +66,7 @@ export function createPatchProxy(path, forbiddenPaths = []) {
 				duplex: 'half'
 			});
 		} catch (err) {
-			logger.debug(err);
-			throw err;
+			handleError(err);
 		}
 	};
 }
@@ -89,8 +86,7 @@ export function createDeleteProxy(path, forbiddenPaths = []) {
 				headers: filterHeaders(request.headers)
 			});
 		} catch (err) {
-			logger.debug(err);
-			throw err;
+			handleError(err);
 		}
 	};
 }
@@ -107,6 +103,21 @@ function checkForbiddenPaths(path, forbiddenPaths) {
 	}
 }
 
+/**
+ * @param {unknown} err
+ */
+function handleError(err) {
+	if (err instanceof Error && err.cause instanceof Error) {
+		// Underlying cause might be a Svelte Kit error
+		error(500, err.cause.message);
+	} else if (err instanceof Error) {
+		error(500, err.message);
+	} else {
+		logger.debug(err);
+		throw err;
+	}
+}
+
 /**
  * Forward only selected headers, to avoid issues like content length mismatch
  * @type {import('fractal-components/types/api').GetHeaders}