AWS was not able to validate the provided access credentials

[pnik073]

I run vagrant up --provider=aws on a (version-controlled) vagrant script from which I have created many times AWS nodes. However, now I get the following error:

There was an error talking to AWS. The error message is shown
below:

Error: Expected(200) <=> Actual(401 Unauthorized)

Response: <?xml version="1.0" encoding="UTF-8"?>
<Response><Errors><Error><Code>AuthFailure</Code><Message>AWS was not able to validate the provided access credentials</Message></Error></Errors><RequestID>a676c766-b59b-4a95-a7a4-3f43fbd0cb64</RequestID></Response>

Based on #372 I have also tried to run ntpdate, but it does not help.

$ sudo ntpdate ntp.ubuntu.com
 8 Apr 17:20:57 ntpdate[26938]: adjust time server 91.189.89.199 offset 0.001902 sec

My system info is:

mac-pnik:awsClusterNode pnik$ vagrant plugin list
vagrant-aws (0.3.0)
vagrant-disksize (0.1.2)
vagrant-google (1.0.0)
xmlrpc (0.3.0)
mac-pnik:awsClusterNode pnik$ vagrant --version
Vagrant 2.0.2
mac-pnik:awsClusterNode pnik$ gem --version
2.7.6
mac-pnik:awsClusterNode pnik$ nokogiri --version
# Nokogiri (1.8.2)
    ---
    warnings: []
    nokogiri: 1.8.2
    ruby:
      version: 2.3.3
      platform: universal.x86_64-darwin17
      description: ruby 2.3.3p222 (2016-11-21 revision 56859) [universal.x86_64-darwin17]
      engine: ruby
    libxml:
      binding: extension
      source: packaged
      libxml2_path: "/Library/Ruby/Gems/2.3.0/gems/nokogiri-1.8.2/ports/x86_64-apple-darwin17/libxml2/2.9.7"
      libxslt_path: "/Library/Ruby/Gems/2.3.0/gems/nokogiri-1.8.2/ports/x86_64-apple-darwin17/libxslt/1.1.32"
      libxml2_patches: []
      libxslt_patches: []
      compiled: 2.9.7
      loaded: 2.9.7
mac-pnik:awsClusterNode pnik$ ruby --version
ruby 2.3.3p222 (2016-11-21 revision 56859) [universal.x86_64-darwin17]

Any recommendations?