diff --git a/src/frontend/apps/desk/src/api/__tests__/parseAPIError.test.tsx b/src/frontend/apps/desk/src/api/__tests__/parseAPIError.test.tsx
new file mode 100644
index 0000000..83bd991
--- /dev/null
+++ b/src/frontend/apps/desk/src/api/__tests__/parseAPIError.test.tsx
@@ -0,0 +1,174 @@
+import { APIError } from '@/api';
+
+import {
+  parseAPIError,
+  parseAPIErrorCause,
+  parseServerAPIError,
+} from '../parseAPIError';
+
+describe('parseAPIError', () => {
+  const handleErrorMock = jest.fn();
+  const handleServerErrorMock = jest.fn();
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('should handle specific API error and return no unhandled causes', () => {
+    const error = new APIError('client error', {
+      cause: ['Mail domain with this name already exists.'],
+      status: 400,
+    });
+
+    const result = parseAPIError({
+      error,
+      errorParams: {
+        name: {
+          causes: ['Mail domain with this name already exists.'],
+          handleError: handleErrorMock,
+        },
+      },
+      serverErrorParams: {
+        defaultMessage: 'Server error',
+        handleError: handleServerErrorMock,
+      },
+    });
+
+    expect(handleErrorMock).toHaveBeenCalled();
+    expect(result).toEqual([]);
+  });
+
+  it('should return unhandled causes when no match is found', () => {
+    const error = new APIError('client error', {
+      cause: ['Unhandled error'],
+      status: 400,
+    });
+
+    const result = parseAPIError({
+      error,
+      errorParams: {
+        name: {
+          causes: ['Mail domain with this name already exists.'],
+          handleError: handleErrorMock,
+        },
+      },
+      serverErrorParams: {
+        defaultMessage: 'Server error',
+        handleError: handleServerErrorMock,
+      },
+    });
+
+    expect(handleErrorMock).not.toHaveBeenCalled();
+    expect(result).toEqual(['Unhandled error']);
+  });
+
+  it('should handle server errors correctly and prepend server error message', () => {
+    const error = new APIError('server error', { status: 500 });
+
+    const result = parseAPIError({
+      error,
+      errorParams: undefined,
+      serverErrorParams: {
+        defaultMessage: 'Server error occurred',
+        handleError: handleServerErrorMock,
+      },
+    });
+
+    expect(handleServerErrorMock).toHaveBeenCalled();
+    expect(result).toEqual(['Server error occurred']);
+  });
+
+  it('should handle absence of errors gracefully', () => {
+    const result = parseAPIError({
+      error: null,
+      errorParams: {
+        name: {
+          causes: ['Mail domain with this name already exists.'],
+          handleError: handleErrorMock,
+        },
+      },
+      serverErrorParams: {
+        defaultMessage: 'Server error',
+        handleError: handleServerErrorMock,
+      },
+    });
+
+    expect(result).toBeUndefined();
+  });
+});
+
+describe('parseAPIErrorCause', () => {
+  it('should handle specific errors and call handleError', () => {
+    const handleErrorMock = jest.fn();
+    const causes = ['Mail domain with this name already exists.'];
+
+    const errorParams = {
+      name: {
+        causes: ['Mail domain with this name already exists.'],
+        handleError: handleErrorMock,
+      },
+    };
+
+    const result = parseAPIErrorCause({ causes, errorParams });
+
+    expect(handleErrorMock).toHaveBeenCalled();
+    expect(result).toEqual([]);
+  });
+
+  it('should handle multiple causes and return unhandled causes', () => {
+    const handleErrorMock = jest.fn();
+    const causes = [
+      'Mail domain with this name already exists.',
+      'Unhandled error',
+    ];
+
+    const errorParams = {
+      name: {
+        causes: ['Mail domain with this name already exists.'],
+        handleError: handleErrorMock,
+      },
+    };
+
+    const result = parseAPIErrorCause({ causes, errorParams });
+
+    expect(handleErrorMock).toHaveBeenCalled();
+    expect(result).toEqual(['Unhandled error']);
+  });
+});
+
+describe('parseServerAPIError', () => {
+  it('should prepend the server error message when there are other causes', () => {
+    const causes = ['Some other error'];
+    const serverErrorParams = {
+      defaultMessage: 'Server error',
+    };
+
+    const result = parseServerAPIError({ causes, serverErrorParams });
+
+    expect(result).toEqual(['Server error', 'Some other error']);
+  });
+
+  it('should only return server error message when no other causes exist', () => {
+    const causes: string[] = [];
+    const serverErrorParams = {
+      defaultMessage: 'Server error',
+    };
+
+    const result = parseServerAPIError({ causes, serverErrorParams });
+
+    expect(result).toEqual(['Server error']);
+  });
+
+  it('should call handleError when provided as a param', () => {
+    const handleErrorMock = jest.fn();
+    const causes: string[] = [];
+    const serverErrorParams = {
+      defaultMessage: 'Server error',
+      handleError: handleErrorMock,
+    };
+
+    parseServerAPIError({ causes, serverErrorParams });
+
+    expect(handleErrorMock).toHaveBeenCalled();
+  });
+});
diff --git a/src/frontend/apps/desk/src/api/parseAPIError.ts b/src/frontend/apps/desk/src/api/parseAPIError.ts
new file mode 100644
index 0000000..e9b52bc
--- /dev/null
+++ b/src/frontend/apps/desk/src/api/parseAPIError.ts
@@ -0,0 +1,83 @@
+import { APIError } from '@/api/index';
+
+type ErrorParams = {
+  [fieldName: string]: {
+    causes: string[];
+    causeShown?: string;
+    handleError: () => void;
+  };
+};
+
+type ServerErrorParams = {
+  defaultMessage: string;
+  handleError?: () => void;
+};
+
+export type parseAPIErrorParams = {
+  error: APIError | null;
+  errorParams?: ErrorParams;
+  serverErrorParams: ServerErrorParams;
+};
+export const parseAPIError = ({
+  error,
+  errorParams,
+  serverErrorParams,
+}: parseAPIErrorParams) => {
+  if (!error || !serverErrorParams?.defaultMessage) {
+    return;
+  }
+
+  let causes: string[] =
+    error.cause?.length && errorParams
+      ? parseAPIErrorCause({ causes: error.cause, errorParams })
+      : [];
+
+  if (error?.status === 500 || !error?.status) {
+    causes = parseServerAPIError({ causes, serverErrorParams });
+  }
+
+  return causes;
+};
+
+export const parseAPIErrorCause = ({
+  causes,
+  errorParams,
+}: {
+  causes: string[];
+  errorParams: ErrorParams;
+}): string[] =>
+  causes.reduce((arrayCauses, cause) => {
+    const foundErrorParams = Object.values(errorParams).find((params) =>
+      params.causes.find((knownCause) => knownCause.match(cause)),
+    );
+
+    if (!foundErrorParams) {
+      arrayCauses.push(cause);
+    }
+
+    if (foundErrorParams?.causeShown) {
+      arrayCauses.push(foundErrorParams.causeShown);
+    }
+
+    if (typeof foundErrorParams?.handleError === 'function') {
+      foundErrorParams.handleError();
+    }
+
+    return arrayCauses;
+  }, [] as string[]);
+
+export const parseServerAPIError = ({
+  causes,
+  serverErrorParams,
+}: {
+  causes: string[];
+  serverErrorParams: ServerErrorParams;
+}): string[] => {
+  causes.unshift(serverErrorParams.defaultMessage);
+
+  if (typeof serverErrorParams?.handleError === 'function') {
+    serverErrorParams.handleError();
+  }
+
+  return causes;
+};
diff --git a/src/frontend/apps/desk/src/features/mail-domains/api/index.tsx b/src/frontend/apps/desk/src/features/mail-domains/api/index.tsx
index 2c5993d..61a928c 100644
--- a/src/frontend/apps/desk/src/features/mail-domains/api/index.tsx
+++ b/src/frontend/apps/desk/src/features/mail-domains/api/index.tsx
@@ -2,4 +2,4 @@ export * from './useMailDomains';
 export * from './useMailDomain';
 export * from './useCreateMailbox';
 export * from './useMailboxes';
-export * from './useCreateMailDomain';
+export * from './useAddMailDomain';