Hi Abishek,
I have received the presentation file shared by you. I have not been able to observe watermark in the shared presentation. I have also observed some notes shared by you regarding Aspose.Slide for Reporting license as well.
Can you please share which version of Aspose.Slides for Reporting Services you are using on your end. I suggest you to please try using Aspose.Slides for Reporting Services 4.11.0 on your end first. Please note that you need to place Aspose.Slides for Reporting Services license file along side Aspose.Slides for Reporting Services installed dll. Also, in your notes you have shared reference of two license files but in actual you have shared only, “Aspose.Slides.Reporting.Services.lic” with us that worked fine on our end. Please also make sure that you have one license file available in your installation but not both.
Many Thanks,