In addition to the below, please disable all 3rd party plugins/applications and test while they are disabled.
If you are still having issues, it may be helpful to know what was happening around the time this started to occur for you. Has anything changed with regards updates, items you might have installed, or indeed server components. In general the steps to try and resolve this initially would be
Clear cache in your support area and check if this is resolved
If there has just been a change on the server, is it something you can switch back and test? If so, try that
Always disable any server side caching you may have
Disable any 3rd party items and check
In the support area, ensure any other items showing in there are addressed