Hi, we are experiencing the below error when trying to add a new item to a managed metadata column. The action IS possible to complete when accessing the site via SharePoint online directly, so its is not a user permission issue and nor is it because the termset has been closed for editing. The issue is the same for all of our users. So what needs to be updated? It has worked fine for years . Error message below and picture attached. Hope you can helt :-)
An error occurred while creating the new term. Please try again.

Error: We have encountered an issue during the login process

Application: Scinaptic.OnePlaceMail.API.ClientIntegration
Method: Void a()
Stack Trace: at Scinaptic.OnePlaceMail.API.ClientIntegration.ModernAuthenticationService.a.a()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Scinaptic.OnePlaceMail.API.ClientIntegration.SharePoint2016Server.e.a()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Scinaptic.OnePlaceMail.API.ClientIntegration.FrmTaxonomyPicker.f.a()