Is it only with one return or multiple returns? If it's with only one particular return, your best bet is to send the return to Support for diagnostic. If it's with multiple returns, try #2 and #3.
Did you try clearing the cache and cookies? This should solve most of the problems. If you are still having problem, it is possible that certain settings/updates in your browser (e.g. extensions) are not fully compatible with ProConnect Tax for whatever reason. I'd then move on to #3 to establish whether it's a problem with a particular browser or PC.
Have you tried using a different browser and/or PC? If this still doesn't work, you may need to speak with Support again to see if they are able to guide you on the diagnostic of your PC/browser configurations or get some professional help since this appears to be an isolated problem not reported by other users and I haven't experienced this myself.
--------------------------------------------------------------------------------- Still an AllStar
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