THE EXECUTE permission was denied on the object 'proc_GetProductVersions' Database '_Config', schema 'dbo'.

We had an issue where search was being used as a core component on the home page for one of the solution's. On further research we identified the it was an access issue on the database side. We are using SharePoint 2013 Enterprise Search which is on Always on Availability Group.

Here are the two errors we got

Error 1: 'The EXECUTE permission was denied on the object 'proc_MSS_GetLease', 

Error 2: THE EXECUTE permission was denied on the object 'proc_GetProductVersions' Database '_Config', schema 'dbo'.

For the Error 1, the search service account needs to have access on SPSearchDBAdmin role on the following databases

• _Search
• _Search_AnalyticsReportingStore
• _Search_CrawlStore
• _Search_LinksStore

For the Error 2, the search service account needs to have  access on WSS_Content_Application_Pools role  for the following databases 

• _Config
• _Admin

After giving the access, bounced the IIS , issue resolved for us. Check the logs to identify the problem.