I’ve found a couple of old threads (4-5 months old) talking about this problem.
https://www.ads-software.com/support/topic/plugin-publish-2-pingfm-you-do-not-have-sufficient-permissions-to-access-this-page-error
https://www.ads-software.com/support/topic/plugin-publish-2-pingfm-not-working
Basically when activated, Publish 2 Pingfm stops access to submenus for other WordPress plugins across the board. The WordPress error “You do not have sufficient permissions to access this page.” appears.
When Publish 2 Pingfm is deactivated, everything works as normal.
I only started using this plugin in the last couple of weeks, so I assume that this problem was solved a few months ago, but has cropped up again with the most recent version of WordPress.
Any workarounds for this, or upgrades expected for the plugin?