# 3270 and 5250 screen errors

Source: https://wndsoftware.com/mainframe-errors/terminal-errors

### 3270 and 5250 screen errors

Look up keyboard, input and data-stream errors on 3270 and 5250 screens.

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### All 28 codes



- [`X (input inhibited)`Keyboard locked, input inhibited](https://wndsoftware.com/mainframe-errors/3270-input-inhibited)
- [`X PROG 750`Invalid 3270 command](https://wndsoftware.com/mainframe-errors/3270-prog-750)
- [`X PROG 751`Invalid character set in an order](https://wndsoftware.com/mainframe-errors/3270-prog-751)
- [`X PROG 752`Invalid buffer address](https://wndsoftware.com/mainframe-errors/3270-prog-752)
- [`X PROG 753`Invalid data or parameter value](https://wndsoftware.com/mainframe-errors/3270-prog-753)
- [`X PROG 754`Order without its parameters](https://wndsoftware.com/mainframe-errors/3270-prog-754)
- [`X PROG 756`Invalid structured field](https://wndsoftware.com/mainframe-errors/3270-prog-756)
- [`X PROG 758`Invalid mode in Set Reply Mode](https://wndsoftware.com/mainframe-errors/3270-prog-758)
- [`X PROG 759`Invalid structured field length](https://wndsoftware.com/mainframe-errors/3270-prog-759)
- [`X PROG 761`Invalid partition ID](https://wndsoftware.com/mainframe-errors/3270-prog-761)
- [`X clock`Host or terminal busy, wait](https://wndsoftware.com/mainframe-errors/3270-x-clock)
- [`X COMM`Communication check](https://wndsoftware.com/mainframe-errors/3270-x-comm)
- [`X -f`Function not available](https://wndsoftware.com/mainframe-errors/3270-x-minus-function)
- [`X SYSTEM`Keyboard locked by the host](https://wndsoftware.com/mainframe-errors/3270-x-system)
- [`5250 error 0004`Typing not allowed in this field](https://wndsoftware.com/mainframe-errors/5250-error-0004)
- [`5250 error 0005`Cursor in protected area of display](https://wndsoftware.com/mainframe-errors/5250-error-0005)
- [`5250 error 0007`Mandatory enter field, data required](https://wndsoftware.com/mainframe-errors/5250-error-0007)
- [`5250 error 0008`Field requires alphabetic characters](https://wndsoftware.com/mainframe-errors/5250-error-0008)
- [`5250 error 0009`Field requires numeric characters](https://wndsoftware.com/mainframe-errors/5250-error-0009)
- [`5250 error 0010`Only characters 0 through 9 allowed](https://wndsoftware.com/mainframe-errors/5250-error-0010)
- [`5250 error 0014`Mandatory fill field, must fill to exit](https://wndsoftware.com/mainframe-errors/5250-error-0014)
- [`5250 error 0015`Check digit error](https://wndsoftware.com/mainframe-errors/5250-error-0015)
- [`5250 error 0016`Field Minus key not valid in this field](https://wndsoftware.com/mainframe-errors/5250-error-0016)
- [`5250 error 0018`Key used to exit field not valid](https://wndsoftware.com/mainframe-errors/5250-error-0018)
- [`5250 error 0019`Dup or Field Mark key not allowed in field](https://wndsoftware.com/mainframe-errors/5250-error-0019)
- [`5250 error 0020`Enter key not allowed in field](https://wndsoftware.com/mainframe-errors/5250-error-0020)
- [`5250 error 0024`Decimal field, entry not valid](https://wndsoftware.com/mainframe-errors/5250-error-0024)
- [`5250 error 0099`Key or function not valid now](https://wndsoftware.com/mainframe-errors/5250-error-0099)


### Working with 3270 & 5250 errors

Start with the exact status-area message. Input inhibition, keyboard state and a rejected host data stream are different problems. Record the session type and the action immediately before the error; do not reset away the evidence before capturing it.

[Browse all 494 error codes](https://wndsoftware.com/mainframe-errors/) · [WND Terminal’s offline code hints](https://wndsoftware.com/docs/code-hints)


### Use WND Terminal with your host system

WND Software develops WND Terminal Emulator for mainframe, IBM i and UNIX access. For connection and keyboard features, see the [3270 terminal emulator](https://wndsoftware.com/3270-terminal-emulator) or [5250 emulator for IBM i](https://wndsoftware.com/ibm-i). [Explain this screen](https://wndsoftware.com/explain-this-screen) provides screen-specific assistance using the model endpoint and context permitted by IT; the reference article explains the code independently.