For Lansweeper on-prem, is it possible to change the web server timeout period?
The timeout can be configured through the IIS Manager. This would be a Microsoft configuration.
The following article from Microsoft might be helpful:
Default Limits for Web Sites <limits> | Microsoft Learn
If you are currently using IIS Express, you will have to reinstall your Lansweeper Web Console under Internet Information Services (IIS) as shown in this KB article: Reinstall the web console - Lansweeper Community