NextUp error catalog

All errors, regardless of severity, come in the same envelope with HTTP 200:

{ "Result": false, "Error": "Descriptive message" }

The only exception is transport errors (DNS, firewall, timeout) which never get past the proxy and come back as HTTP 502 with a body:

{ "Result": false, "Error": "Proxy error: connect ENETUNREACH 1.2.3.4:8888 - ..." }

Error categories

1. Authentication errors

Message	Cause	Recommendation
AuthenticationToken lipseste, este invalid sau a expirat.	Token missing / invalid format / expired	Call GetAuthenticationToken again.
Invalid credentials.	Wrong UserName/Password/Database	Check the combination against the mock's predefined values.

2. Validation errors

Message	Cause	Recommendation
Parametrul "X" este obligatoriu.	Field missing from Params	Add the field. The list of required ones is in the API Reference.
Campul "Method" este obligatoriu.	The envelope has no Method	Check the top level of the JSON.
Payload-ul nu este JSON valid: ...	Malformed JSON	Validate with a linter.
Comanda trebuie sa contina cel putin o linie.	Lines: []	Add at least one line with ArticleCode, Quantity, UnitPrice.
Factura trebuie sa contina cel putin o linie.	Same	Same

3. Business errors (NextUp-specific)

These are functional errors of the ERP. The Mock Server reproduces them identically.

Internal code	Message	Cause	Recommendation
duplicate	Partener cu codul "X" exista deja.	Code conflict on AddPartner	Generate a different code or use AddOrUpdatePartner.
duplicate	Articol cu codul "X" exista deja.	Code conflict on AddArticle	Same.
not_found	Partenerul cu codul "X" nu a fost gasit.	Lookup on a non-existent code	Check with GetAllPartners.
not_found	Articol cu codul "X" nu a fost gasit.	Lookup on a non-existent code	Check with GetAllArticles.
not_found	Cursul valutar pentru simbolul "X" nu este disponibil.	GetExchangeRate with an unknown symbol or a future date	Check the symbol (EUR, USD, ...).
missing_vat	Cota TVA cu id X nu exista.	Invalid VATRateId on AddArticle	Use one of 1 (19%), 2 (9%), 3 (5%), 4 (0%).
insufficient_stock	Stoc insuficient pentru articolul "X" in depozitul N.	AddSaleInvoice with quantity > available stock	Check with GetStocksForArticleByCode; do an entry with AddEntryStock first.

4. Transport errors (proxy)

These appear before reaching NextUp ERP. They come from our proxy, not from the ERP.

Message	Cause	Recommendation
Proxy error: connect ENETUNREACH ...	The LAN cannot see the ERP	Check the IP in .env, the ping, the firewall. Switch to mock to keep working.
Proxy error: connect ETIMEDOUT ...	The ERP does not respond	NextUp is probably stopped. Start it via Utilitare → Servicii WEB → Panou de control → Porneste.
Endpoint-ul "X" nu exista.	Wrong URL in the client (the mock responds this way on 404)	Check the spelling: /NextUpServices/Services/POST/ (with the trailing slash).
Metoda "X" nu este implementata in mock server.	Wrong method name, or it does not exist in NextUp	Check in the API Reference.

HTTP status codes (proxy + mock)

Code	When it appears	Response body
200	Success AND business errors (NextUp convention)	{ Result, Error }
400	Malformed headers at the proxy	ad-hoc JSON text
404	Wrong URL (at the mock)	{ Result:false, Error:... }
502	Proxy could not connect to upstream	{ Result:false, Error:"Proxy error..." }

Never rely on the HTTP status to decide success

NextUp always returns 200 when the connection succeeded. The only real indicator is Result !== false && Error === null. Build your SDK wrapper with this convention in mind.

Recommended error-handling algorithm

"Strict" mode for integrations

For critical integrations, we recommend applying the following rules before marking a call "OK":

1. HTTP status === 200
2. body.Error === null (or missing from the response)
3. body.Result !== false
4. For Add*, body.Result has the shape { Id: number, ... } or is a number > 0
5. For Update* / Delete*, body.Result === true

Any deviation from these rules should trigger a retry or a high-severity log entry.

Spec version

The error messages reproduced here correspond to NextUp v7.47+. Older versions may use English messages or slightly different formatting. When integrating with old ERPs, do not match on the full string but on a substring (error.includes('insufficient')).