luceos Yes, but that has to happen for composer.json, composer.lock and especially the whole vendor directory.
Hi there! I was able to finally solve it by adding my user to the group www-data via: usermod -aG www-data "user"
However, I have encountered another error when trying to install the "Payments" extension. This is the error report:
Your requirements could not be resolved to an installable set of packages.
Problem 1
- blomstra/payments[0.3.0, ..., 0.5.9] require brick/money 0.5.0 -> satisfiable by brick/money[0.5.0, 0.5.1, 0.5.2, 0.5.3].
- blomstra/payments[0.1.1, ..., 0.1.2] require flarum/core 0.1.0-beta.15 -> found flarum/core[v0.1.0-beta.15, v0.1.0-beta.16] but it does not match your minimum-stability.
- blomstra/payments[0.2.1, ..., 0.2.3] require flarum/core 0.1.0-beta.16 -> found flarum/core[v0.1.0-beta.16] but it does not match your minimum-stability.
- brick/money[0.5.0, ..., 0.5.3] require brick/math 0.7.3 | 0.8.0 | 0.9.0 -> found brick/math[0.7.3, ..., 0.9.3] but the package is fixed to 0.10.2 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command.
- Root composer.json requires blomstra/payments * -> satisfiable by blomstra/payments[0.1.1, ..., 0.5.9].
Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.
Installation failed, reverting ./composer.json and ./composer.lock to their original content.
The Flarum version displayed in my admin panel is 1.5.0.
Sorry for asking asking your help a number of times @luceos. I hope I'm not abusing your kindness. Thanks again!