Refer to the following link as we had the same problem:
JOSFER95's suggestion fixed the issue for several of us.
I had luck by uninstalling the APP from the play store. Once uninstalled, an update option appeared that was not there before. I clicked it and it updated and reinstalled with all my messages still intact. I was afraid if used the clear data option from the application manager that it would erase all my current messages. Hope that helps and works for you as well.
I apologize for this inconvenience with the Verizon Messages application. I know how important it is to be able to use this application to communicate via text message. Let's work on getting this resolved, please update the Verizon Messages app on your device and test the application. http://vz.to/2bcfv1l Please keep us posted with your progress and let us know if you are still experiencing issues.
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gersong_vzw, your solution does not fix this. The solution is to remove and reinstall Verizon Messages. I did this yesterday and now all my crashing and hanging issues on my LG V20 have disappeared. You do have to resetup your preferences so know what they are if you're not sure, but it doesn't remove any texts and problem solved.
If, btw, anyone is experiencing smartwatch delays, unpair/factory reset your watch and let it all resync and those problems go away too.