
Also, there is a strange captioned back button:

@kerlama: I think you are talking about Magento 2.2.4 instead of 2.2.3? If that's the case, then this bug was already reported before in https://github.com/magento/magento2/issues/14968
If you agree this is the same issue, can you close this one, so there is only a single issue tracking the same problem, thanks!
Ah sorry, didn't read your issue completely, you're indeed upgrading to 2.2.4. Let me close it as a duplicate of #14968 then.
@hostep ok, thanks :)
Update theme using terminal its working for me .
INSERT INTO core_config_data (config_id,scope,scope_id,path,value) VALUES ('19','default',0,'design/theme/theme_id',5);
or update
UPDATE core_config_data SET value=5 where config_id=19;
@abhisekhranjan well, I guess that's not the proper solution :)
INSERT INTO core_config_data (config_id,scope,scope_id,path,value) VALUES ('19','default',0,'design/theme/theme_id',5);
or update
UPDATE core_config_data SET value=5 where config_id=19;
Set value= as theme id listed then run the command
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy -f
php bin/magento indexer:reindex
php bin/magento cache:flush
chmod -R 777 var
chmod -R 777 pub