My issue is very similar to Aspose Total license Expired Error
The environments are the same with the exception that the one that is not working is a virtual machine. Does the dll need to make an HTTP call to verify the expiration date of the library?
I have observed your comments that you are getting the issue on a certain server but not reproducing the issue with same license and code on other servers. It seems to be issue related to access of license file on your problem generating server. Aspose.Slides does offer you the support of validating if the license is applied in your application or not. You may please try using the following sample code on your end to serve the purpose.
License lic = new License();
//Issue in license, please reload the license
When you say to reload the license, do you mean to just use SetLicense() again? What’s the point if it will be the same result?
No message will appear, that’s just a comment inside the brackets of the if statement.
I have observed your comments and like to share that the sample code that I have shared with you is helpful in verifying if your license file is applied in your application or not. If for any reason in your application for example your application may spawn a new thread, in that case you need to verify if your license file is applied in thread you are using Aspose.Slides instance. If for any reason, the false value is returned, you can simply reload the license. I hope this will be understandable. If there is still an issue then please share the working sample project reproducing the issue along with all platform and other details on machine where things are failing.