2013 CU 15 standard. Both servers have all roles and works as DNS round robin HA and DAG along with Win 2008 R2 witness server.
I have moved most of the users to office365 with hybrid deployment. Only about 4 active users left on premise.
Now, when office365 users send email to on premise users they get error '400 4.4.7 Message delayed'. Also, one of the Exchange server is almost 0 on C-drove memory as folder "Inetpub" for ISS has take 215 GB of storage space with Exchange log.
My Exchange server was configured with E and F drive for logs and database.
May be delayed or failed email for on premise But I am sceptic about rebooting when available space is almost 0

Please help...


I did not find the right solution from the Internet.

References
https://partnersupport.microsoft.co...e/...8eba8c3c?auth=1

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