Workaround: start a local world, stay there a couple of seconds, leave the world -> servers are working...
Tested on Nintendo Switch and xbox one
same here...
what helps sometimes:
switch from online to local network (Y on Main Screen) and back again brings servers back
You can "workaround" this by doing it as follows:
Create an Item (which registers to inventory as expected ) and take care, that the format_version is >= 1.16.100
and name it in a way, that there is a relation to the block you want to create.
In the item, use the minecraft:block_placer compontent to place the corresponding block.
That's the way, all the "good working" addons are written, as from version 1.16.0 on, the custom blocks do not work anymore...
"format_version": "1.17.0",
"minecraft:item": {
"description": {
"category": "nature",
.....
"components": {
"minecraft:block_placer": {
"block": "....."
.....