Sympy not found in current path but it´s installed - visual-studio-code

Question

I had been working all afternoon with Julia when suddenly SymPy stopped working. It tells me that I should add SYMPA but SymPy is already there. The weirdest thing of all is this only happens inside of Visual Studio Code, as the Julia program can perfectly run SymPy. This is the error that pops up whenever I try to run using SymPy in VSC
ERROR: ArgumentError: Package Sympy not found in current path.
- Run `import Pkg; Pkg.add("Sympy")` to install the Sympy package.
Stacktrace:
[1] macro expansion
# .\loading.jl:1163 [inlined]
[2] macro expansion
# .\lock.jl:223 [inlined]
[3] require(into::Module, mod::Symbol)
# Base .\loading.jl:1144
[4] eval
# .\boot.jl:368 [inlined]
[5] include_string(mapexpr::typeof(REPL.softscope), mod::Module, code::String, filename::String)
# Base .\loading.jl:1428
[6] invokelatest(::Any, ::Any, ::Vararg{Any}; kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
# Base .\essentials.jl:729
[7] invokelatest(::Any, ::Any, ::Vararg{Any})
# Base .\essentials.jl:726
[8] inlineeval(m::Module, code::String, code_line::Int64, code_column::Int64, file::String; softscope::Bool)
# VSCodeServer c:\Users\humbe\.vscode\extensions\julialang.language-julia-1.38.2\scripts\packages\VSCodeServer\src\eval.jl:233
[9] (::VSCodeServer.var"#66#70"{Bool, Bool, Bool, Module, String, Int64, Int64, String, VSCodeServer.ReplRunCodeRequestParams})()
# VSCodeServer c:\Users\humbe\.vscode\extensions\julialang.language-julia-1.38.2\scripts\packages\VSCodeServer\src\eval.jl:157
[10] withpath(f::VSCodeServer.var"#66#70"{Bool, Bool, Bool, Module, String, Int64, Int64, String, VSCodeServer.ReplRunCodeRequestParams}, path::String)
# VSCodeServer c:\Users\humbe\.vscode\extensions\julialang.language-julia-1.38.2\scripts\packages\VSCodeServer\src\repl.jl:249
[11] (::VSCodeServer.var"#65#69"{Bool, Bool, Bool, Module, String, Int64, Int64, String, VSCodeServer.ReplRunCodeRequestParams})()
# VSCodeServer c:\Users\humbe\.vscode\extensions\julialang.language-julia-1.38.2\scripts\packages\VSCodeServer\src\eval.jl:155
[12] hideprompt(f::VSCodeServer.var"#65#69"{Bool, Bool, Bool, Module, String, Int64, Int64, String, VSCodeServer.ReplRunCodeRequestParams})
# VSCodeServer c:\Users\humbe\.vscode\extensions\julialang.language-julia-1.38.2\scripts\packages\VSCodeServer\src\repl.jl:38
[13] (::VSCodeServer.var"#64#68"{Bool, Bool, Bool, Module, String, Int64, Int64, String, VSCodeServer.ReplRunCodeRequestParams})()
# VSCodeServer c:\Users\humbe\.vscode\extensions\julialang.language-julia-1.38.2\scripts\packages\VSCodeServer\src\eval.jl:126
[14] with_logstate(f::Function, logstate::Any)
# Base.CoreLogging .\logging.jl:511
[15] with_logger
# .\logging.jl:623 [inlined]
[16] (::VSCodeServer.var"#63#67"{VSCodeServer.ReplRunCodeRequestParams})()
# VSCodeServer c:\Users\humbe\.vscode\extensions\julialang.language-julia-1.38.2\scripts\packages\VSCodeServer\src\eval.jl:225
[17] #invokelatest#2
# .\essentials.jl:729 [inlined]
[18] invokelatest(::Any)
# Base .\essentials.jl:726
[19] macro expansion
# c:\Users\humbe\.vscode\extensions\julialang.language-julia-1.38.2\scripts\packages\VSCodeServer\src\eval.jl:34 [inlined]
[20] (::VSCodeServer.var"#61#62")()
# VSCodeServer .\task.jl:484

Answer 1

This sounds like a problem with the environment you are using. What is it saying in the bottom left of VSCode about the environment?
If it says there something like "Julia 1.8.3", you are using the overall installation. I could imagine that this is not the case.
In every folder you can create a specific environment. Go into the package mode by typing ] in the REPL. Then activate the "folder" environment like this
(#v1.8) pkg> activate .
and your prompt will change to
(your_folder) pkg>
This is strongly encouraged by the way.
You can then in the package mode (]) see the installed packages (st) and add (add [package]) and remove some ( rm [package]) as well.