> For the complete documentation index, see [llms.txt](https://docs.payfacto.com/payfacto-knowledge/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.payfacto.com/payfacto-knowledge/uk-and-intl/applications/securepay/troubleshooting.md).

# Troubleshooting

## Troubleshooting

### Microsoft .NET Framework 3.5 is missing

#### Issue Description:

While attempting to install STPISecure, an error message is displayed:

<figure><img src="/files/Vf1whLErlJRPa5vRAXxw" alt=""><figcaption></figcaption></figure>

STPISecure requires Microsoft .NET Framework 3.5.

Please use Windows Update / Windows Features to install this version, and then re-run the installer.

#### Solution:

Install Microsoft .NET Framework 3.5 through Windows Update or use the "Turn Windows features on or off" option from Add/Remove programs to enable .NET Framework 3.5.

<figure><img src="/files/97DSrss07alFEHPmitEf" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/3itzDjrS7mUPA74hKlkq" alt=""><figcaption></figcaption></figure>

Once Microsoft .NET Framework 3.5 is installed, retry installing STPISecure.

***

### Java is missing

#### Issue Description:

While attempting to install STPISecure, an error message is displayed:

<figure><img src="/files/dpUAsH6z6YrlSJ7A6Oto" alt=""><figcaption></figcaption></figure>

STPISecure requires Java version 1.8 or newer.

Please install this separately and then re-run the installer.

#### Solution:

Download and install Java from the Oracle website:

<https://www.java.com/en/>

Once Java is installed on your system, retry installing STPISecure.

&#x20;