Error connecting Sharepoint/Exchange online when installing VB for MS365

[sasilik]

Decided to try Veeam Backup for Microsoft 365 but got stuck with install when it configured Entra app and tried to connect Sharepoint/Exchange Online. First it could not configure Entra app but it was solved with running IISCrypto and disabling unnecessary stuff. After that Entra App creation was successful, Connected to MS Graph, EWS, Powershell but failed to connect to SP/EO with same error as previously:
[Warning] Warning: The SSL connection could not be established, see inner exception.
[Warning] Warning: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host..
[Warning] Warning: An existing connection was forcibly closed by the remote host.

Looked at article about MSO and ciphers https://learn.microsoft.com/en-us/purvi ... encryption and IISCrypto output and needed cipher suites were in place:

Code: Select all

Configured Cipher Suites: TLS_CHACHA20_POLY1305_SHA256,TLS_AES_256_GCM_SHA384,TLS_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384,TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256

Firewall was OK, https inspection was disabled. Then found another article which mentioned that cipher suite order is also important
https://learn.microsoft.com/en-us/troub ... 12-support
And one in Veeam forums viewtopic.php?f=2&t=76311&start=0
Did - Enable-TlsCipherSuite -Name "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384" -Position 0
And after that SP/EO connection was also successful. Is these things so self-evident that there is no need to mention it in User Guide or they are mentioned somewhere and I just missed them?