Are you trying to perform a fresh install of DNN or an upgrade? Which version(s) of DNN? Is this on a server or in a local development environment? If local, are you using any tools (e.g., nvQuickSite) to assist with the installation? If this is on a server, can you explain a bit more about your procedure for the install/upgrade?

This was a clean working install following the DNN9 Series Video on a local Win 11 SSD C: drive using DNNDEV.ME site in folders websites\dnndev.me. Using SQL Studio 19, Visual studio 22, and suggested IIS elements from the Video, this is DNN 9.13.3. All was working well until I used the create a new module from the series. Upon loading the module the site was damaged and had to be rebuilt. I deleted the files in dnndev.me folder and reinstalled and have had this error ever since. I have been using DNN for the last 10 years with the last build 3 years ago on WinHost. I am trying to develop a new site to sell my photos from my photography business. I have a masters in computer science if that helps.

For local installs these days I use https://www.nvquicksite.com/ which makes it quick.

When you say "create a new module" are you talking about Module Creator? I thought that was removed in recent versions. So was DNN working until the point of creating a new module, if so was a template used or what? Can you link to the series you are talking about... Many videos are for older versions or refer to some older templates that may potentially have not been maintained much.

This was Video 10 installing a new extension in the series by Chris Hammond. I followed all steps as suggested. Got new templates for VS for DNN and installed, build went without error. Series DNN9 Series Video 1 - Installing IIS, Visual Studio 2017 and SQL Server 2016 Express (youtube.com). What is this error trying to tell me, I could not find a refference in any config file? I am now in the process of deleting IIS, the folders and starting over to see if that will clear the error condition. DNN has always been a breath holder on install, but this is a new one for me. I would be nice if the install were a bit more bullet proof. I like the manual install, but I will try your suggestion on using the link. Windows 11 won't allow the .msi file in the down load even though I say I trust it.

I've seen this error in the past when I've messed up something about the domain name.  I missed putting it somewhere, but I don't recall which place.  🤔

I'm guessing in DNN though... 

The DNS and IIS were fine, but DNN was expecting a different domain name and it didn't like the one it was being given (per the configuration I had in DNN).  

OK, I hate to admit this, but I had changed the system name to shorten it without thinking. I have uninstalled IIS, emptied the recycle bin, optimized the C: drive and restarted the system. I reinstalled and setup IIS, created the folders to dnndev.me, loaded the files from DNN 9.13.3 into the folder and ran the install and all is back to normal. Thank you Will, for the hint on the domain name issue. Here is a case where the error message was misleading and if possible, could be improved. Be careful what you change when using DNN, it all makes sense now, but would have not gotten here without the help from Will. Thanks again.

Awesome - glad you figured it out! 🎉

I agree about the error message, but when I finally tracked down the issue and cause back then, the error was "technically" correct. However, the root cause was a much more deeply rooted (and suppressed) error related to the domain name. I had to do some serious debugging and stepping through the code to track it down back then. 

Now, I'm just SUPER paranoid about getting things like that correct.  So much so, that I don't manually type any of that stuff.  It's all automation and copy/paste wherever possible.  😉 

David, I can't get your https://www.nvquicksite.com/ to download correctly in Win 11 even though I say it is safe. Any ideas here?