Microsoft have annouced they will be restricting access to Microsoft Teams data via EWS from the 30th September see https://devblogs.microsoft.com/microsoft365dev/restricted-access-to-microsoft-teams-data-via-ews-starts-september-30-2022/ . If you are using EWS to access any teams data you will need to move to the Graph API's https://docs.microsoft.com/en-us/microsoftteams/export-teams-content one thing to note is "Microsoft Teams APIs in Microsoft Graph that access sensitive data are considered protected APIs" so there are some extra steps and time you need to access this data and be aware of the potential need to pay for that access eg "On July 5th 2022, metered consumption is active, and will be billed through an Azure subscription" ref https://practical365.com/teams-export-graph-apis/.
If your getting an error such as Application is over its MailboxConcurrency limit while using the Microsoft Graph API this post may help you understand why. Background The Mailbox concurrency limit when your using the Graph API is 4 as per https://docs.microsoft.com/en-us/graph/throttling#outlook-service-limits . This is evaluated for each app ID and mailbox combination so this means you can have different apps running under the same credentials and the poor behavior of one won't cause the other to be throttled. If you compared that to EWS you could have up to 27 concurrent connections but they are shared across all apps on a first come first served basis. Batching Batching in the Graph API is a way of combining multiple requests into a single HTTP request. Batching in the Exchange Mail API's EWS and MAPI has been around for a long time and its common, for email Apps to process large numbers of smaller items for a variety of reasons. Batching in the Gr...