Error map
Document failed validation MongoDB: MongoServerError: Document failed validation (code 121)
MongoDB · layer 5, Data
Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (12)
HTTP 422 Unprocessable Content
The request is well-formed, but the data fails validation (e.g. invalid email, missing required field).
ORA-00942: table or view does not exist
Oracle can’t see the table — it doesn’t exist, is in another schema, or you lack privileges on it.
java.lang.IllegalArgumentException
A method rejected an argument value as invalid.
pydantic_core._pydantic_core.ValidationError: 1 validation error for Model
Data didn’t match a Pydantic model — a field is missing, has the wrong type, or fails a constraint.
MySQL ERROR 1406: Data too long for column
The value is longer than the column allows (e.g. 300 characters into VARCHAR(255)), and strict mode rejects it instead of truncat…
MySQL ERROR 1067 (42000): Invalid default value for 'created_at'
A column’s DEFAULT isn’t allowed in the current SQL mode — classically '0000-00-00 00:00:00' with NO_ZERO_DATE.
CastError: Cast to ObjectId failed for value "x" (type string) at path "_id"
A value that isn’t a valid 24-hex-character ObjectId was used in an _id query.
ValidationError: User validation failed: email: Path `email` is required.
A document failed Mongoose schema validation before saving.
strict decoding error: unknown field "spec.template.spec.containers[0].ports[0].protocl"
The manifest contains a field the API schema doesn’t know — a typo, wrong indentation, or a field from another API version.
GraphQL: Cannot query field "x" on type "Y"
The query asks for a field that doesn’t exist in the server’s schema (or isn’t available on that type).
MethodArgumentNotValidException: Validation failed for argument [0]
Bean Validation (@Valid with @NotNull, @Email, @Size…) rejected the request body.
ERROR: invalid input syntax for type uuid: "x"
A value that isn’t a valid UUID was compared with or inserted into a uuid column.
Two steps away (36)
HTTP 400 Bad Request
The server could not understand the request because its syntax, headers or body are malformed or invalid.
HTTP 415 Unsupported Media Type
The server refuses the request because the body’s Content-Type isn’t one it accepts.
HTTP 409 Conflict
The request conflicts with the current state of the resource — e.g. a duplicate or an edit based on an outdated version.
MySQL ERROR 1146 (42S02): Table 'db.table' doesn't exist
The query references a table that MySQL can’t find in that database.
sqlite3.OperationalError: no such column: x
SQLite can’t find the column — missing migration, typo, or a string written in double quotes.
SQL Server: Invalid object name 'x'. (Msg 208)
The table/view doesn’t exist in the current database or schema.
java.lang.NumberFormatException: For input string: "x"
A string couldn’t be parsed as a number — it’s empty, has spaces/commas, is too large, or isn’t numeric.
java.lang.IllegalStateException
A method was called when the object wasn’t in the right state for it.
java.lang.ArithmeticException: / by zero
Integer division or modulo by zero.
MySQL ERROR 1048 (23000): Column 'x' cannot be null
An INSERT/UPDATE put NULL into a NOT NULL column.
MySQL ERROR 1264 (22003): Out of range value for column 'x' at row 1
A number is too large (or negative for UNSIGNED) for the column type.
MySQL ERROR 1366 (HY000): Incorrect integer value: '' for column 'x' at row 1
An empty string or non-numeric text was inserted into an INT column under strict mode.
MySQL ERROR 1062 (23000): Duplicate entry for key
An INSERT/UPDATE would create a duplicate value in a PRIMARY or UNIQUE key.
MySQL ERROR 1366: Incorrect string value: '\xF0\x9F\x98\x80' for column
The text contains characters (usually emoji) that the column’s character set can’t store — the column or connection is `utf8`/`ut…
MySQL ERROR 1005 (HY000): Can't create table (errno: 150 "Foreign key constraint is incorrectly formed")
A foreign key definition is invalid — the referenced column’s type, index or charset doesn’t match.
MySQL ERROR 1054 (42S22): Unknown column in 'field list'
The query references a column that doesn’t exist in the table (or an unquoted string being read as a column).
MySQL ERROR 1007 (HY000): Can't create database 'x'; database exists
CREATE DATABASE ran for a database that already exists.
MySQL ERROR 1008 (HY000): Can't drop database 'x'; database doesn't exist
DROP DATABASE targeted a database that isn’t there.
MongooseError: Operation `users.find()` buffering timed out after 10000ms
Mongoose queued a query waiting for a connection that never opened.
MongooseServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017
The MongoDB driver couldn’t find a reachable server for the connection string.
MongoServerError: E11000 duplicate key error collection: db.users index: email_1 dup key
An insert/update violated a unique index in MongoDB.
Express: req.body is undefined / {} (body parser missing)
Express didn’t parse the request body because no body-parsing middleware matched the request’s Content-Type.
API Error: Invalid type — expected integer, received string
A request field has the wrong data type — a string where the API expects a number, a number where it expects a boolean, an object…
API Error: Invalid parameter value — must be one of the allowed values / out of range
The field has the right type but a value the API doesn’t allow — not in the list of accepted options, too small or large, too lon…
ERROR: null value in column "x" of relation "y" violates not-null constraint
An INSERT/UPDATE put NULL into a NOT NULL column.
ERROR: new row for relation "x" violates check constraint "y"
A value failed a CHECK constraint (e.g. price > 0, status IN (…)).
ERROR: invalid input syntax for type integer: "abc"
A string couldn’t be converted to the column’s type (integer, numeric, boolean, date…).
CORS Error: No 'Access-Control-Allow-Origin' header is present
The browser blocked a cross-origin request because the server’s response didn’t include the CORS headers allowing your site’s ori…
HTTP 200 OK (but something is still wrong)
The request succeeded at the HTTP level — yet the page is blank, the data is wrong, or an error is hidden inside the response bod…
API Error: Request failed schema validation (must NOT have additional properties / Additional properties are not allowed)
The JSON body doesn’t match the endpoint’s schema — an unknown property, wrong nesting, or a missing required object.
UnsatisfiedDependencyException / NoSuchBeanDefinitionException: No qualifying bean of type 'X' available
Spring couldn’t find (or choose) a bean to inject.
The dependencies of some of the beans in the application context form a cycle
Two or more Spring beans depend on each other through constructors, and Spring Boot 2.6+ forbids cycles by default.
Web server failed to start. Port 8080 was already in use.
Spring Boot couldn’t bind its embedded server port because another process uses it.
ERROR: value too long for type character varying(255)
A string exceeds the column’s varchar length.
ERROR: numeric field overflow — A field with precision 5, scale 2 must round to an absolute value less than 10^3
A number doesn’t fit the column’s numeric(precision, scale) or integer range.
ERROR: operator does not exist: integer = text
A comparison or operation mixes types PostgreSQL won’t implicitly convert.
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