Update: This issue has been fixed in the latest version of Citrix Receiver for Mac.
Fixed an issue where sessions would disconnect resulting in an error message indicating that “The remote SSL peer sent a bad MAC Alert.” [LC4367]
For more information, refer to Citrix Documentation – Fixed issues in Citrix Receiver for Mac 12.
Workaround:
- Enable Session Reliability
OR
- Uninstall Receiver for Mac 12.1 and re-install 12.0 (this version does not have the issue).
Refer to the download site for further information: 12.1 download page