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HangFire Recurring Job Does Not Work Giving Error Sometimes

Hello, we are using HangFire 1.7.28 with .Net core net5.0.
Our jobs are getting errors randomly, and the error messages are not understandable, the code does work without a problem but the jobs are getting errors, here is one of them:

System.InvalidOperationException: Recurring job can't be scheduled, see inner exception for details.
 ---> Hangfire.Common.JobLoadException: Could not load the job. See inner exception for the details.
 ---> System.InvalidOperationException: The type `Sahin.Smart.Business.Services.IUserService` does not contain a method with signature `SendCard()`
   at Hangfire.Storage.InvocationData.DeserializeJob()
   --- End of inner exception stack trace ---
   at Hangfire.Storage.InvocationData.DeserializeJob()
   at Hangfire.RecurringJobEntity..ctor(String recurringJobId, IDictionary`2 recurringJob, ITimeZoneResolver timeZoneResolver, DateTime now)
   --- End of inner exception stack trace ---
   at Hangfire.Server.RecurringJobScheduler.ScheduleRecurringJob(BackgroundProcessContext context, IStorageConnection connection, String recurringJobId, RecurringJobEntity recurringJob, DateTime now)

The other error is like this:

  System.InvalidOperationException: Recurring job can't be scheduled, see inner exception for details.
 ---> Hangfire.Common.JobLoadException: Could not load the job. See inner exception for the details.
 ---> System.TypeLoadException: Could not load type 'Sahin.Smart.Business.Services.IFileService' from assembly 'Sahin.Smart.Business, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.
   at System.Reflection.RuntimeAssembly.GetType(QCallAssembly assembly, String name, Boolean throwOnError, Boolean ignoreCase, ObjectHandleOnStack type, ObjectHandleOnStack keepAlive, ObjectHandleOnStack assemblyLoadContext)
   at System.Reflection.RuntimeAssembly.GetType(String name, Boolean throwOnError, Boolean ignoreCase)
   at Hangfire.Common.TypeHelper.TypeResolver(Assembly assembly, String typeName, Boolean ignoreCase)
   at System.TypeNameParser.ResolveType(Assembly assembly, String[] names, Func`4 typeResolver, Boolean throwOnError, Boolean ignoreCase, StackCrawlMark& stackMark)
   at System.TypeNameParser.ConstructType(Func`2 assemblyResolver, Func`4 typeResolver, Boolean throwOnError, Boolean ignoreCase, StackCrawlMark& stackMark)
   at System.TypeNameParser.GetType(String typeName, Func`2 assemblyResolver, Func`4 typeResolver, Boolean throwOnError, Boolean ignoreCase, StackCrawlMark& stackMark)
   at System.Type.GetType(String typeName, Func`2 assemblyResolver, Func`4 typeResolver, Boolean throwOnError)
   at Hangfire.Common.TypeHelper.DefaultTypeResolver(String typeName)
   at Hangfire.Storage.InvocationData.DeserializeJob()
   --- End of inner exception stack trace ---
   at Hangfire.Storage.InvocationData.DeserializeJob()
   at Hangfire.RecurringJobEntity..ctor(String recurringJobId, IDictionary`2 recurringJob, ITimeZoneResolver timeZoneResolver, DateTime now)
   --- End of inner exception stack trace ---
   at Hangfire.Server.RecurringJobScheduler.ScheduleRecurringJob(BackgroundProcessContext context, IStorageConnection connection, String recurringJobId, RecurringJobEntity recurringJob, DateTime now)

and sometimes the job just doesn’t work, without any record in database for hangfire.

We added the jobs like this:

recurringJobManager.AddOrUpdate<IUserService>("User_SendCard", x => x.SendCard(), "0 8 * * *", TimeZoneInfo.FindSystemTimeZoneById("Turkey Standard Time")); // At 8.00am daily

This issue is started lately, in around last 2 months. What my be the problem?

The error was related to DevOps in our case. The stage and live environments were getting confused and mixed into each other which was causing this problem.