Hi,
You didn't say what the model number of the unit was but according to this [https://acerrorcode.com/onida-split-air-conditioners-error-codes.html|link] an E5 error means compressor overload protection. This is assuming that Onida uses the same error codes for all their models.
Here's a [https://beebehvac.com/4-common-causes-hvac-compressor-overload/|link] that generally describes what can cause this to happen but perhaps you should contact a reputable, professional air conditioning repair service and ask them to check it out.