SharePoint 2013 Server - The status code of response is '500'. The status text of response is 'System.ServiceModel.ServiceActivationException'.

SharePoint 2013 Server - Unexpected response from server. The status code of response is '500'. The status text of response is 'System.ServiceModel.ServiceActivationException'

When everything is working fine and suddenly you start receiving an error while the SharePoint page loads, "Unexpected response from server. The status code of response is '500'. The status text of response is 'System.ServiceModel.ServiceActivationException'". That too from only one front end server. First thing first;

• Remove the front end server from the load balancer.
• Now your site is fine for end users, but not for you ;)
• Login to the front end server where the issue is occurring.
• The issue occurs mostly because of occupied memory. If memory utilization is more then you will receive this error.
• Right click on Task manager and check the memory occupied.
• The users who are logged into the servers and forgot to log off has occupied space.
• Right click on the username and force log off them; except your userid ;)
• Refresh the SharePoint site, the error is no more.
• Enable the server in the load balancer again.

Cheers !

Workflow changes in SharePoint Designer not taking effect

I was using a SharePoint Designer workflow and one day I had to make some changes to the workflow. The changes were not taking any impact. After so many attempts I executed the below steps which fixed the issue.

Soltuion 1:
A quick solution is to disassociate the workflow, make changes to the workflow again and associate it back with the list.
Steps:
Go to List Settings > Workflow settings > Remove a workflow > Select Remove option from the radio button and click OK. Then open the workflow again from SharePoint designer, make some changes and click Finish, so it is associated again.
Your changes should now appear.
Solution 2:
Steps:
If workflow A is not working, create another workflow B. Create a valid any IF condition in workflow B and close the workflow. It will generate the XOML rules file. Open the XOML rules file and XOML workflow file of workflow A in notepad and copy paste the contents in the XOML files of workflow B (your new workflow). Now open your workflow B, you can see everything got copied from A. Disassociate workflow A from your list and associate workflow B.
Solution 3:
Steps:
Delete the files in from \local settings\app data\msft\websitecache and \app data\msft\sharepoint esigner\proxyassemblycache folders. This cleared things out.

Cheers !