NO matching autocommands: User NvimMkdpRpcExit

**Describe the bug**
When I try to run :MarkdownPreview from the command line in a README.md file, instead of getting the file produced, I get the error message

```
No matching autocommands: User NvimMkdpRpcExit
```

**To Reproduce**
Steps to reproduce the behavior:
1. Follwing the README.md I had added to .vimrc
```
Plug 'iamcco/markdown-preview.nvim', { 'do': { -> mkdp#util#install() }, 'for': ['markdown', 'vim-plug']}
```
2. The run :PlugInstall
3. open a README.md
4. Run :MarkdownPreview

**Expected behavior**
In the past I would expect to see a web page open with the HTML displayed

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Desktop (please complete the following information):**
- OS: MacOS Monterey 12.1
- Machine; Apple MacBook Pro M1 Max

Log:

```
Not sure where is the log file?
```