Предстоящие 1,0 выпуска Матрицы (доступный теперь от ответвления мерзавца) будут допускать интерактивные сессии с удаленным концом.
Errors like these are usually problems related to DNS resolution.
Try to run nslookup locally on your exchange server:
set type=mx
gmail.com
Look at the results (run the gmail.com query several times), and see if stays coherent. Check with an outside client against a different DNS server and see if it matches.