hello -I'm seeing quite a few of these errors in the smtp outbound convo logs, and the emails appear not to be sent:


2025-08-19 13:34:39,207 - [ 810855] S 2025-08-19 13:34:39,207 - [ 810844] C --> 451 Internal resource temporarily unavailable - community.mimecast.com/docs/DOC-1369#451 [zcUxN7cxPJKtfmE5IJ_wZA.uk321]
2025-08-19 13:34:39,207 - [ 810844] S 2025-08-19 13:34:39,207 - [ 810844] C --> 221 Service closing transmission channel [zcUxN7cxPJKtfmE5IJ_wZA.uk321]
2025-08-19 13:34:39,223 - [ 810856] S

is the issue  our end, with the Xeams setup, or with the client? Can anything be done about it?

many thanks in advance,

adrian