Here's the first part of the error text:

Server Error in '/' Application.
Microsoft.Web.Services3.Security.SecurityFault: The signature or decryption was invalid ---> System.Security.Cryptography.CryptographicException: WSE523: The CipherData contents are invalid.
at Microsoft.Web.Services3.Security.Cryptography.SymmetricEncryptionFormatter.Decrypt(Byte[] data)
at Microsoft.Web.Services3.Security.EncryptedData.Decrypt(XmlElement encryptedElement)
--- End of inner exception stack trace ---
at Microsoft.Web.Services3.Security.EncryptedData.Decrypt(XmlElement encryptedElement)
at Microsoft.Web.Services3.Security.EncryptedData.Decrypt()
at Microsoft.Web.Services3.Security.Security.LoadXml(XmlElement element)
at Microsoft.Web.Services3.Security.Security.CreateFrom(SoapEnvelope envelope, String localActor, String serviceActor)
at Microsoft.Web.Services3.Security.ReceiveSecurityFilter.ProcessMessage(SoapEnvelope envelope)
at Microsoft.Web.Services3.Pipeline.ProcessInputMessage(SoapEnvelope envelope)
at Microsoft.Web.Services3.WseProtocol.FilterRequest(SoapEnvelope requestEnvelope)
at Microsoft.Web.Services3.WseProtocol.RouteRequest(SoapServerMessage message)
at System.Web.Services.Protocols.SoapServerProtocol.Initialize()
at System.Web.Services.Protocols.ServerProtocolFactory.Create(Type type, HttpContext context, HttpRequest request, HttpResponse response, Boolean& abortProcessing)
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.Services.Protocols.SoapHeaderException: Microsoft.Web.Services3.Security.SecurityFault: The signature or decryption was invalid ---> System.Security.Cryptography.CryptographicException: WSE523: The CipherData contents are invalid.
at Microsoft.Web.Services3.Security.Cryptography.SymmetricEncryptionFormatter.Decrypt(Byte[] data)
at Microsoft.Web.Services3.Security.EncryptedData.Decrypt(XmlElement encryptedElement)
--- End of inner exception stack trace ---
at Microsoft.Web.Services3.Security.EncryptedData.Decrypt(XmlElement encryptedElement)
at Microsoft.Web.Services3.Security.EncryptedData.Decrypt()
at Microsoft.Web.Services3.Security.Security.LoadXml(XmlElement element)
at Microsoft.Web.Services3.Security.Security.CreateFrom(SoapEnvelope envelope, String localActor, String serviceActor)
at Microsoft.Web.Services3.Security.ReceiveSecurityFilter.ProcessMessage(SoapEnvelope envelope)
at Microsoft.Web.Services3.Pipeline.ProcessInputMessage(SoapEnvelope envelope)
at Microsoft.Web.Services3.WseProtocol.FilterRequest(SoapEnvelope requestEnvelope)
at Microsoft.Web.Services3.WseProtocol.RouteRequest(SoapServerMessage message)
at System.Web.Services.Protocols.SoapServerProtocol.Initialize()
at System.Web.Services.Protocols.ServerProtocolFactory.Create(Type type, HttpContext context, HttpRequest request, HttpResponse response, Boolean& abortProcessing)

Hello,

Please go to IIS and select each of the SolidCP sites, then go to Machine Key --> click generate, and click apply.

Once this is complete run a iisreset and see if that helps with this error.

Thanks,

Trevor Robinson