"Not Found" error when trying to add GCE provider

Trying to add Google Compute Engine provider in Cloud Providers, getting the following error though:

What I did to troubleshoot so far:

All of above led to that I see these lines now:

[----] I, [2018-05-29T08:31:37.238563 #7656:ae9138]  INFO -- : MIQ(MiqServer#populate_queue_messages) Fetched 1 miq_queue rows for queue_name=generic, wcount=4, priority=200
[----] I, [2018-05-29T08:31:37.317911 #11619:ae9138]  INFO -- : MIQ(MiqGenericWorker::Runner#get_message_via_drb) Message id: [231], MiqWorker id: [12], Zone: [default], Role: [ems_operations], Server: [], Ident: [generic], Target id: [], Instance id: [], Task id: [], Command: [ManageIQ::Providers::Google::CloudManager.raw_connect?], Timeout: [600], Priority: [100], State: [dequeue], Deliver On: [], Data: [], Args: ["prime-tractor-204908", "********", {:service=>"compute"}, nil, true], Dequeued in: [2.080843039] seconds
[----] I, [2018-05-29T08:31:37.318072 #11619:ae9138]  INFO -- : MIQ(MiqQueue#deliver) Message id: [231], Delivering...
[----] E, [2018-05-29T08:31:37.503222 #11619:ae9138] ERROR -- : MIQ(MiqQueue#deliver) Message id: [231], Error: [Not Found]
[----] I, [2018-05-29T08:31:37.503472 #11619:ae9138]  INFO -- : MIQ(MiqQueue#delivered) Message id: [231], State: [error], Delivered in [0.185394027] seconds
[----] I, [2018-05-29T08:31:37.505568 #11619:ae9138]  INFO -- : MIQ(MiqQueue#m_callback) Message id: [231], Invoking Callback with args: ["Finished", "error", "Not Found", "nil"]
[----] I, [2018-05-29T08:31:37.505762 #11619:ae9138]  INFO -- : MIQ(MiqTask#update_status) Task: [15] [Finished] [Error] [Not Found]

However, I cannot get what is not found.
Could you please point me to a correct direction?

It is still relevant for me.
I assume that google cloud engine is unable to find my key/service account/project name/whatever. What would be a command to run this manually to play around?

Upd: chatroom at https://gitter.im/ManageIQ/manageiq/providers helped to figure out that indeed gce api was deprecated and fix was just released yesterday:

Will update my instance and post back with results.