To workaround the issue increase the session.maxSessionsPerUser value on the affected vCenter.
1. Take a snapshot of the vCenter as a best practice precaution
2. Connect to VCSA via SSH & login with root user:
3. Take a backup of the /etc/vmware-vapi/endpoint.properties file:
cp /etc/vmware-vapi/endpoint.properties /etc/vmware-vapi/endpoint.properties.backup
4. Edit the endpoint.properties file
vi /etc/vmware-vapi/endpoint.properties
5. Remove the comment on the session.maxSessionsPerUser line and increase the value from the default of 550 to 1000.
a) When the maxSessionsPerUser limit is increased to match the total maxSessionCount (=1000) this can open the door to an intended or unintended DoS attack - as one single user can eat up all the available sessions, all other users will not be able to create a session.
b) When the maxSessionsPerUser is increased to 1000, the maxSessionCount should also be increased to 1500.
c) Very important. If the maxSessionCount is increased, then the APIs performance and scaling is no longer guaranteed - it may degrade. Also, the memory that the vAPI Endpoint service will need increases, and thus it is recommended to also increase its memory, following the KB: Manually increasing the heap memory on vCenter Server Components
6. Restart the vCenter services for changes to take effect:
service-control --restart vapi-endpoint
7. Validate again the vCenter cloud account in Aria Automation