SPD workflow Failed on start (retrying)

I have been wrestling with this issue for about 60 days, the issue occurs when you create a simple OOB SPD workflow or even a Nintex workflow.

The solution to this is two parts

PART I

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The service account should be a part of

1. Looked at the groups in the local machine

· WSS_WPG

· WSS_ Restricted

· WSS_Admin_WPG

· IIS_WPG

2. Checked on the SQL management studio  > security > logins > Service account > properties > server roles were given as dbcreator > security & system admin > public

      Looked in user mappings the service account  was set db owner

3. >> Looked in the application content database in SQL

      service account should be  is a db owner

4. In  Central Admin page  > policy for web application > add service account as full control 

5. CA > operations tab > update farm administrators group > service account is added there

6. looked in the site > site settings > site collection administrator

7. looked in the component services > dcom config > IIS admin service > security > added the service account to launch and activation > access permissions > and Configuration permissions .

After doing all these settings the service account must have all the require permissions

PART II

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Second part of the solution is change the service account from the central admin page & run an IIS reset

this is the main key and you will have to compulsorily do this to resolve the issue

hope it works for you