While we already have a longer timeout for fetching keys, it looks like the AD token is only 10s which is sometimes not enough depending on amount of network devices you use going in and out of Azure.
[09:25:11]Starting the build on the agent hostname01
[09:25:21]Error fetching Azure access token: Read timed out: java.net.SocketTimeoutException: Read timed out, see teamcity-server.log for details
[09:25:22]Retrieved 0 secrets from Azure Key Vault
While we already have a longer timeout for fetching keys, it looks like the AD token is only 10s which is sometimes not enough depending on amount of network devices you use going in and out of Azure.