Cannot open my cloud home word doc in android phone

I cannot open a word doc in my android phone recently. I have installed MS Word app in the phone but I cannot open a word doc. I have no problem to open PDF files. I use Oneplus 8 Pro phone with dual SIM cards. I uninstalled the MS word app and reinstalled again, but I still cannot open a word doc. This has never happened before. Can anyone please help me? Thanks in advance!!

@mantis1 Are the documents on your My Cloud Home?

yes, they are in my cloud. i just cannot open them in my android phone.

I can open PDF files in My Cloud in my android phone but cannot open word doc in the phone using MS word app. I uninstalled and installed MS word app for a few times but still cannot open a word doc in my cloud in the phone. This just has happened recently. Very strange and annoying! Can anyone help me? Thanks in advance!!