Moksha,
Which version of Eclipse are you working with? CodeMix will not work with Eclipse 2021-12 and newer. Please note that CodeMix has already reached its end of life and no new releases or fixes will be made.
See here for more details : https://www.genuitec.com/products/codemix/end-of-life-notice/
MyEclipse 2022 is the alternative based on Language Server tech : https://www.genuitec.com/products/myeclipse/
We have a 30 day free trial for MyEclipse. You can evaluate it and then buy if it fits your requirements.
If you must work with CodeMix then the only workaround is to install it on a prior Eclipse version (Eclipse 2021-09 or earlier with Java 11 along with this patch).
If an existing CodeMix installation suddenly stopped working, then please share the Eclipse version details, OS and version details and the .log file located at workspace dir/.metadata/.log (rename it to .txt and attach it here) to help us investigate further.
Hope this helps. Do let us know if you have any further questions.
–Swapna
Genuitec Support