Error in retrieving the report from crystal web service . report content is empty

6/14/2022 6:01:14 AMThe input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.    at System.Convert.FromBase64_Decode(Char* startInputPtr, Int32 inputLength, Byte* startDestPtr, Int32 destLength)
   at System.Convert.FromBase64CharPtr(Char* inputPtr, Int32 inputLength)
   at System.Convert.FromBase64String(String s)
   at Ifs_ReportService.base64Decode(String data) in c:\inetpub\wwwroot\IFSCRWebSetup\App_Code\Service.cs:line 1773
6/14/2022 6:01:14 AM[IFSCRWebSetup-ERROR in [GetSavedPDFReport] Error in exporting the report in PDF format.
6/14/2022 6:01:14 AM[IFSCRWebSetup-Error in base64DecodeThe input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.    at Ifs_ReportService.base64Decode(String data) in c:\inetpub\wwwroot\IFSCRWebSetup\App_Code\Service.cs:line 1785
   at Ifs_ReportService.GetSavedPDFReport(String FileName, String ParameterValues, String LangCode) in c:\inetpub\wwwroot\IFSCRWebSetup\App_Code\Service.cs:line 235