VMware VM backups failed post uprgading to VBR 13

[AnubhavSh]

Most of the VM backups failing the day we have upgraded to VBR v13, required port communication is enabled however backups could not run which were running without any errors earlier witg VBR v12.
Also, there are 7 out of 12 proxies which are affected post upgrade, are there any changes happened for TLS communication or FIPS protocol or any additional ports to be opened.
Somehow if I used backup server as a backup proxy for 2 VMware clusters, the backups are happening fine but can't use backup server for each of these clusters.

Error:
Error: read: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond [system:10060]
Getting VM info from vSphere
Error: read: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond [system:10060]

I haven checking with the support on the Case # 08095755, but no luck on this issue. Did anyone encounter this issue or if why is this behavior with VBR v13?

[PatrikSE]

I have the same issue. We have three sites running vSphere, protected thru the same master VBR server. After upgrading from Veeam B&R 12 to 13, all backups for all sites fails. Same error message as you have, is presented for every VM. Meanwhile, all replication jobs keep running successfully.

I attempted to setup a test backup job and lock the backup proxy to the VBR server itself and then the backup succeeds over nbd. (The regular proxies runs either Hot Add mode or SAN mode, depending on site.) Forceing a virtual proxy to use nbd doesn't help.

I also have a support case running Case #08099646

[PatrikSE]

What I found is that if we reverse the traffic initialization by enabling the setting "Run server on this side" for the proxy servers, the backup runs successfully. Network team can still not see any blocks in the network and the Windows firewall on the VBR server and Windows based proxy neither registers any blocks. But wanted to share this temporary fix to get the backups running until Veeam Support gets back.