right click paste suddenly stopped working in outlook email

Normally I can use my mouse to highlight, copy and paste text and URL's from just about anywhere (files on my computer or online) and paste into the body of an email in outlook - have been doing this without any issue for more than five years.

Now, suddenly and without any changes made by me and without any obvious explanation -or solution- I can only copy and paste ONE time after a fresh sign in. Thereafter I cannot copy and paste with my mouse - when I attempt to, a different window opens, it has a paste option in the menu but it does nothing other than close the window.

I can paste with the mouse in the to, cc and subject fields as usual / normal - only the body of the email is affected.

I can paste into the body of the email from the keyboard with Ctr-V - please don't answer with that as the solution - it isn't, it's an alternative.

I am looking to fix the mouse problem - it is how I work and want to continue to work.

Thanks

p.s. Instructions here suggest inserting a screen shot - made two, tried inserting / uploading here but ... that appears not to work either - I don't see any screen shots here do you ?