Step1: First see the issue check the ERA Explorer and ERA Server An updated version is present or not. If not then update it.
Step2: Close the Firewall and IPversion6 (IPversion6 is present in the Network and Sharing Center option in the control panel) disable the antivirus and net-protector.
Step3: Do the cache clear of ERA by taking action (Windows+R button, type %appdata%, delete ERA explorer and ERA related files) do the cache clear of System by taking action (Windows+R button, type %temp%, press enter key, and delete all files it will skip the files which are running on a current Basis)
Step4: Login to the learner to see the issue will get resolved.
In case of any query, kindly raise the support ticket for the same.