If multiple concurrent requests are made to pages that require the fetching of credentials, the following error results:
The 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.
Note: This error is logged in the log file, not on the web page.
EPiServer.MarketingAutomationIntegration.Marketo 3.2.5; EPiServer.MarketingAutomationIntegration.Marketo 3.1.1; (Or a related package);