We have some old CRM servers running 2011 as part of a custom solution that was put in back in 2010. We are unable to upgrade the servers easily due to the number of custom plugins and lack of CRM developers to re-code to a new version. There is already a project underway to overhaul the solution overall. Recently our central team which manages ADFS upgraded the server to 2016 from 2012, which of course means that ADFS has been upgraded.
We have a very strange intermittent issue, we have load of calls being made to CRM via the discovery service however one call from a specific application seems to have an issue with Tokens some of the time. Restart the CRM IIS service and the error clears for time before returning. The error is along the lines of security token is invalid. All other request work however at the same time.
I am struggling to understand what do next, any points would be great.
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