Acronis Cyber Protect 15.0.1.26172 - no web console after updating

After Updating to latest Acronis Cyber Backup Version (15.0.1.26172) iam not able to login to Webconsole anymore (while Backups seem to get written to our storage):

While updating i had to ignore this issue (after retry it reoccured frequently).

After finishing the update, it seems not all services are installed anymore. When trying to launch the Acronis Installer again we receive: Service AcrMngSrv is not installed.
 

web_server.log is full of errors like:

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "D:\Acronis\Acronis\WebServer\wcs\web\rest.py", line 73, in wrapper
    session = web_session.get()
  File "D:\Acronis\Acronis\WebServer\wcs\web\session.py", line 858, in get
    timeout=DEFAULT_TIMEOUT, data=session_data, session_id=session_id)
  File "D:\Acronis\Acronis\WebServer\wcs\web\session.py", line 735, in create
    timeout=timeout, data=data, session_id=session_id)
  File "D:\Acronis\Acronis\WebServer\wcs\web\session.py", line 176, in __init__
    session=self)
  File "D:\Acronis\Acronis\WebServer\wcs\web\pool.py", line 86, in obtain
    e.to_error(), None, get_language)
wcs.web.exceptions.ApiException: {"date":"2021-02-17T12:24:04.243913+00:00","troubleshoot":null,"reason":"internalError","context":{"operation":"unknown","cause_str":"SocketError: No connection could be made because the target machine actively refused it.","_internal":"0:20:-1"},"serCode":"0x02E50032","origin":{"code":50,"text":"SocketError: No connection could be made because the target machine actively refused it.","linetag":"0xE6F03FBB50041841","suberror":null,"fields":{"Code":"10061","$module":"asyncipc_vsa64_26172"},"module":741},"cause":"SocketError: No connection could be made because the target machine actively refused it.","effect":"Error"}
2021-02-17 13:24:04,244 10152 | None | -GET | /api/ams/session/configuration? | (1 in progress) | (1.009949 response time) | (0 bytes response size) | (500 response status) | session: None | AMS shard: None
2021-02-17 13:24:04,244 7044 | None | -GET | /api/ams/session? | (0 in progress) | (1.006949 response time) | (0 bytes response size) | (500 response status) | session: None | AMS shard: None
 

When trying

"D:\Acronis\Acronis\RegisterAgentTool\register_agent.exe" -s mms -o register --update -a localhost:9877

we receive:

Error 0x2de0002: Registration has failed.Ensure that service mms is running on the machine with address localhost and listens on port 43234.

telnet localhost 43234 also showing not response.

Installation logfiles also showing:

1: [16:04:05:280]: (ONCRpcPortMap) StopServices: StopService::Execute: Error 0x2be0002: Failed to open service 'ONCRpcPortMap'.

| line: 0x474cd3234f674bb4
| file: d:\1053\inst_supp\service_supp\impl\windows_service.cpp:438
| function: ServiceSupp::WindowsService::OpenServiceA
| $module: custom_actions_ab_vsa64_s_26172

| error 0xfff0: The specified service does not exist as an installed service
| line: 0xbd28fdbd64edb8f8
| file: d:\1053\core\common\error.cpp:314
| function: Common::Error::AddWindowsError
| code: 0x80070424
| $module: custom_actions_ab_vsa64_s_26172

]: (AmsWebServer) StopServices: StopService::Execute: Error 0x2be0002: Failed to open service 'AmsWebServer'.
| line: 0x474cd3234f674bb4
| file: d:\1053\inst_supp\service_supp\impl\windows_service.cpp:438
| function: ServiceSupp::WindowsService::OpenServiceA
| $module: custom_actions_ab_vsa64_s_26172
| error 0xfff0: The specified service does not exist as an installed service
| line: 0xbd28fdbd64edb8f8
| file: d:\1053\core\common\error.cpp:314
| function: Common::Error::AddWindowsError
| code: 0x80070424
| $module: custom_actions_ab_vsa64_s_26172

1: 16:13:00.375: MSI_TRACE(tib_mounter): Device {00007FF8-F6A8-3ACF-4200-000010F8CF3A} has not been found: error=259

Anybody experienced similar issues while updating to latest version?

Is there a way to fix this issues or do we need to revert to the last version (via Backup).