Dear Ivan,
I received your e-mail. Thanks for your further information.
Spire.Doc.dll v5.1.4.53020 should be Spire.Doc.dll v5.1.2.53020? Because Spire.Doc Standard Edition doesn't have the dll version 5.1.4.53020.
In web app, we suggest you apply license by license key.
Please try to add these code to the load license into Global.Application_Start method.
code:
String key= "key_doc"; //The string "key" should be the value of the Key attribute of the element License of your Spire.Doc license xml file
Spire.License.LicenseProvider.SetLicenseKey(key);
http://www.e-iceblue.com/Tutorials/Lice ... ply_by_KeyThe latest Standard version is Spire.Doc for .NET Standard Edition Version:5.2 at present. Please try this version if still not work.
Please feel free to contact us if you have any problems.
Best Regards,
Amy
E-iceblue support team