Have experienced [still unsolved], same issue with notifications to Workflow Group Members when actions are triggered. This issue, for us, has existing since the first Joomla! 4 Beta. We have upgraded continuously and tested the Workflow and the failure to send, via email, the notifications to the addresses who have indicated for the various participant roles.
Operating on Linux Server - fully functional at GoDaddy.

@200MPHMEDIA could you post a link to your previous reports so that we can get them all in one place please

I reported the same problem in 08/2020: [#30361] - [4.0] Notification in Workflow can't be read by not administrator user

@paternax I have fixed your problem which is actually something different to this.

@200MPHMEDIA @joaoparao the problem is that the workflows notifications are sent using the com_messages component and that will only send a message to user with admin access and NOT to the user who triggered the notification.

@bembelimen @chmst you are more familiar with workflows than me. Could you take a look please.

Suggestions -

1. ignore/remove that limitation in com_messages
2. filter the list of user groups (and users) that can be set to receive notifications to exclude those that are excluded by com_messages

@brianteeman Hello and thanks for the tips. I had already adopted the second without results. Now I try to apply the first ... Thanks Joao

I have found the problem in the code which I highlight in this issue #37745 and I just await a decision on the way forward.

Great @brianteeman!!! Look forward to your solution.
Thanks Joao